I think it's a very minor downside, actually.
a minor downside is more along the lines of heavy armour :
- low tech ships because they're slow anyway and they have goods arcs to the point where unless you -really- need to look forward, it's not going to be a performance hit.
- mid line ships because they have their jets.
- high tech because they are maneuverable enough to the point where even if they take a hit, they can still perform fairly well.
possibly sitting uselessly in space for much longer and having to be more overly critical about everything elses positions (enemies, allies, missiles, allied missiles, etc) and your fleet possibly being denied some heavy firepower for even much longer, when compared to pretty much getting free armour and just being more reckless and relaxed, is a fairly huge downside, and a much more unfair one to the player who wants a more faster fleet than the player who wants a more meatier fleet.
going further with this example:
in the previous(current? i suppose) aug engine downside, you didn't have to pay
as much to get back to where you were (if you so desired to do so) and maybe get a little more than that, with this, you cannot.
also, with the vent cut, it wasn't down to luck / incompetence (either on your part or the AIs). you could prevent an overload by shutting down the shields and backing off to vent, however no amount of eye laser glares or harsh words would get those missiles to not slam into your engines, or those pesky ships to not mess up your rear.
for heavy armour users, you can get XX%
more maneuvering for w/e amount of OP with somewhat no downside(may or maynot have to sacrifice some heavy OP guns for it), this bonus was MUCH more higher than the amount of venting you could get.
this was fairly ok, as just like the heavy armour downside, you could cancel it out (or not worry about it altogether, in some circumstances), however now you cannot and you have to pay significantly more to lessen the effect whereas heavy armour ships can get a rather large gain.
inb4 "if heavy armour is so great, why doesn't everyone use it then": different styles are different, i could live / workaround my ships not turning as well. some people may not.*
If your engines are getting hit to the point where they're flaming out, you've got bigger problems.
not really, there have been far far far far far more times when tele-ships / flanking ships / missiles have gotten lucky to do JUST ENOUGH for me to flameout and make me drift uselessly and my fleet got denied their heavy support firepower, than situations where my engines cutout in / lead to fatal situations, in which case 2x repair rate is redundant unless the enemy ships suddenly get a severe case of OOOOOH SHINY! and leave me be and disperse.
inb4 " my experiences are different! you're doing it wrong / stop trolling / play the game ": such is the way of games like these. naturally mine are going to be different from yours, whats happening to you isn't the same that's happening to everyone else.*
but I do feel the downside of it is getting blown way out of proportion.
and i feel you're vastly downplaying it so people just go along with it with the least amount of fuss, your blanket statement above kindof proves that.
* not specifically aimed at you alex.