To start with first know that I am an avid player of the original Halo Wars and have played extensively from release day till current day.
Game mode: The domination game mode is one that does not seem that impressive when it comes to a strategy game. one complaint many people had in halo wars 1 was the lack of depth. This mode only seems to add to this as it is more about capturing points fast rather than building up an army. If this was a third game mode in the original it would be the least played due to not really having many player vs. player engagements.
New game mode ideas: I feel if you insist on a game mode like domination you should make king of the hill with one hill that moves to various locations, just like in the fps halo games. this would create more action rather than just roaming from capture point to capture point with no battles like in the current domination. for this mode it might be best if main bases were indestructible and same with main base turrets( which should be spawned from start). possibly allow individual buildings to be destroyed to slow the enemy down though. another possible game mode could be a four person free for all standard battle (eliminate enemy bases and units to win).
Overall beta review: To be quite honest i think the game deviates way too much from the original. If I am playing halo wars 2 I want to feel some similarity from halo wars 1, and sadly I don't. Truth be told most of the fan base was not looking for something brand new, but rather an upgrade that went a little more in depth than the original.
If the beta was symbolic of the full version to be released then please name it something else because it does not coincide with the original halo wars and does not deserve to be in its family.
Base structure: The base structure in the original halo wars looked pretty good and it was simple. I'm really not sure why the base in the beta had to be completely changed from original. as it stands buildings in the beta almost look detached from the main base and so do turrets. A base is should be the entirety of buildings and the main complex connected as one as in the original game. also i do not see the reason behind changing so many of the building names from the original, they were fine as is. It is very hard to tell when buildings will be completely built and same with extra bases. the original game had a good system for this, my advice for base structure just copy the original bases and buildings without name changes, and just upgrade the graphical details of each building. Also generators are clutter the base and design should maybe be reverted to one small wind turbine or even a solar panel.
Resource system: I am undecided about whether the old system needed more depth. What i would say about the new system is that you need to take tech off of base upgrades and make them into reactor buildings as they were before. currently as it stands it is just too easy to upgrade and keep tech levels. in the original game enemy players could come over and slow you down by destroying reactors, this option is now gone because you would have to destroy entire base which is much more difficult. as for the addition of power i sort of like the attempt at more depth but this setup is not it. currently power is basically supplies with a different name and instead of adding a new element you just copied supplies and made a new name. one suggestion i have is to make power into real energy rather than a numerical value like supplies. you could have a energy meter which actually powers the electrical components of your base. example: no power = no new building of units. have power slowly recharge over time but i guess possibly maybe faster with generator buildings? im not a huge fan though of having to build all these generator buildings so maybe have one generator allowed(like covenant temple in original) which can be upgraded maybe like 3-5 times which would increases the recharge rate of power. this energy would recharge on its own without this one building but this would be like a field armory for energy upgrades only. Keep supply pads as they are now and were in the original. no change needed to them.
Map hooks: bring back all the hooks from the original game, they were good except the cannon on tundra. I feel mini bases are pointless and should just go back to being one or two slot building spaces. reactor hook, population hook, sniper towers, shield walls, and healing spires should all be back. I feel these hooks should be as in original game where you put infantry in and leave him in there if you want the benefits of the hook. Supply hooks as well should reappear but maybe they would be with your current setup of capture them with infantry but you can leave when you have fully captured it. assuming you remove power from its current state (which you need to) do not have many hooks on the map as currently there is in beta.
Leaders: Please do not take away from the original aspect of covey leader and unsc 3 Spartans with leader power. This made the first halo wars have differences between leaders and factions. if they are made similar as they currently are with hero's then you are actually taking away from the diversity in the game. I will say i like the idea of an upgrade tree for certain powers as you have it currently. also please bring back super units and unique units for covey. these also helped each leaders uniqueness. I cannot say because you have not released it entirely but a new faction plus the old 2 would be welcomed, but again keep them diverse if possible.
graphics: I realize this is just a beta but the graphics are horrendous. they have lost their mojo and toughness from the original game. instead they look like cartoons and mega blocks. even though halo universe is not real the graphics should try to make it look real. units should look mean and tough made of metal rather than look like flimsy plastic. one thing that i would say is that the last halo wars was a little dark so i do think the game still needs to have brightness in it as the beta has.
units: to start i do like that mainline infantry and scouts are all in main base, but please make all infantry and scouts able to collect supplies. i also like the upgrade in each building to upgrade the speed and damage of all units in that building. again this is just a beta but please still bring back old units such as gremlin, elephant, jackals and others. but cobra did need to go. please bring back pelican dropship and covey teleporter (or a dropship).
suggestions: I know console can be more difficult but adding more precise micro capability is possible and needs to at least be attempted. also unit formations should be added. this would give a new dimension to strategy. Maybe add like four quick keys to d-pad where you would activate by holding down another button. examples could be circle an area as painted with the paint brush tool, get in rows like ancient battles used to be, split army in half ( just would be quicker than paint brush, and maybe one other type. make the attack cursor lock to enemy. Please create a line paint brush for unit movements and make it just follow the exact line so you could technically draw any path not just straight line. i don't know your plan but please do not let units get vetrancy from killing rebel (AI) units and bases.
add onto original game you don't have to change everything around.