TL;DR: Me too! I’d rather speak up than regret not doing so.
Honestly, I tried proton a while back, and while I didn’t like it, I could kinda adapt to it. Note that I do generally like change: I thought the quantum redesign was great. I even liked Windows 8 (I know, right?)
But as far as removing the compact option goes, I’m not sure if I’d be pissed off or just annoyed, were it to go through (My honest opinion - I don’t mean to flame anyone).
When I tried proton + compact mode on nightly, it seems to cause some issues with the “Playing” indicator, because firefox tries to place it on top, instead of on the side. I would imagine this is what is prompting the removal - likely among other issues that I’m unaware of.
But the way I see it: here it’s proton that’s the problem, not the other way around.
Does compact mode have low engagement? I would think so. But I’d seriously doubt that engagement numbers are low among those who are aware of it. For me it was an obvious choice once I found out about it.
But even if the overall engagement numbers are low; If it is high among the heavy firefox users, that would mean that it’s removal would constitute what I’d call a “papercut”. There is a reason for the phrase: “Death by a thousand papercuts”.