@time_drainer problem is that ENGINES generate slowly over time, while control just slams the points. Why are there no control engines? And I do not speak of Hazards, as it is completely different mechanic. More like a Vampire Unit that gets attached to a unit and drain it till it's death, slowly moving the points from one side of the board to the other. Why Axemen swing their axe but they themselves are not doing damage, but only buffing themselves? Why are there no such units? We had enforcers but they overnerfed the SO HARD that they are unplayable now. Etc. etc.
Yes the whole point of engines are, that they generate points over time. If they get shutdown early, you lose points, if they don't, they generate more points than you could get with any immediate point effect card (in the same tier). Remove the option to shut them down and they just become objectively better than other cards.
(Btw. Enforcers got nerfed
exactly because they were slamming points immediately
in addition to being an engine. I agree though that now they are too weak, while they were too strong before.)
Regarding "control engines": the point of engine control is that it shuts down an engine. If it can only "eventually, maybe" kill an engine, it's not control, it's just an engine itself.
That said if most of current engines would also get nerfed, as in they wouldn't generate too much points or get "out of range" too fast, I would be okay with less instant bronze elimination. Also if I can't kill an engine with a bronze card, it also shouldn't be able to get resurrected by one.
Just a couple engines that would be problematic by removing bronze elimination and leaving them as they are: Mangonels, Greatswords (in my opinion they already are) and pretty much anything that buffs itself by more than 1 points per turn (as you can't catch up with them before getting behind in points). On the other hand cards like Dragoons and Savage Bears would probably be okay.
Also Silver and Gold engines should probably also be out of range for lower tier elimination, but should provide a way to play around them even if they don't get removed immediately, e.g. you can damage one of opponent's cards against Butterfly, but you can't do too much against Odrin - other than kill all of his units, which is hardly achievable in most cases.