What I would change about the warzone formula, if it would return, is few things such as, making the reqs unlimited & free to all people firstly, then weapons/vehicles/other could be unlocked as the match goes on depending on their level to avoid joining players being on disadvantage while also lessening complete spawn killing of losing team which could be result of quitters/afkers, this could definitely lessen it's nature as microtransaction seller while also having various level of weapons but it could be a way to keep more static playerbase.This could in theory be replaced by a better system. Look at Command & Conquer Renegades for example...it never had any form of REQ system but it required teams to work together, to make certain resource collectors keep resources flowing so players can buy vehicles, etc...
Also they would need teams to project them, in theory resources from the vehicles could be used to restock bases.
Alternatively I think the best option might be sticking to BTB then adding AI, making it so we can hijack enemy AI vehicles since hated not being able to do that in WZ.
As for WZ: Firefight I would ditch the insane homing attacks, get back to surviving as many waves as possible, avoid any situations where we have to get to an objective to defend since most of the time that would lead to a fail due to lack of time to get there.
As for quitters/afkers...in theory this could lead to AI bots that could replace them until someone JIP then the AI would leave the battlefield after a short timer. Also it could be possible to buy units to protect bases instead of them just spawning randomly after being dead for a certain time...to avoid cheap deaths by AI.
There truly are many ways to change Warzone so it wouldn't be dependant on reqs, given if they want to keep the gametype in the game at all. So in other words, your suggestions seem to be a viable option in my mind.
As for bots in the matches, it has been something under discussion on some topics, it's not necessarily the best one but still an option.
The bots cant fully replace human players but even as a temporary supplement, would they be worth the work required? For example, possibly needing a varying effectiveness level, which would include accuracy & reaction time for example, depending on the skill level of the players on board for balancing reasons, next would be that what is the primary objective for the AI? Would it pursue objectives relentlessly, would it seek the company of human players, defend a point or what exactly?
And as to afkers, not much bots would do with them, if there is a player present then bot shouldn't spawn.
And even if the idle timer would be decreased that can be easily passed by just taping the controller & report system more than likely would be abused. There is no easy solutions for those problems hence why they are years old problems.
But that is it's own discussion entirely.