Honestly it could be construed as either or both; the issue is with a combination of a weapon which is absolutely brutal in a certain type of situation (CQC) and a type of environment oriented around that same situation which is crucial to map control (Biolabs). Changing Biolabs to be more open would dilute their role (providing a CQC environment for infantry), so the solution is to dilute the strength of the problem weapon (Scatmaxes). In short, I think that they are proportionally more effective in their role than just about anything else. This could be remedied in a number of ways but I think that the most elegant would be to markedly decrease their accuracy beyond very close range (~3 meters). That'd let them maintain their role as a CQC powerhouse and siegebreaker while also giving people a chance to engage them at fairly close ranges without being instantly blown away, as well as increasing the importance of engineer support and covering fire when they can't just pop around doorways.
I am perfectly fine with NC maxes killing everythng under 5m. I personally have no real problem dealing with them anyway, but I join people saying you shouldn't whine about getting insta-killed if you found yourself inside the scatmax killzone.
A TR max can be killed even at its ideal range if you're careful. If you run into a scatmax at its ideal range, you're dead.
Yes, and why is that a problem? the TR ideal range is far bigger than the NC's, so you have more trouble to get out of it, and NC max will have far more trouble getting you inside its killzone.
smaller killzone = lower TTK, and I'm fine with that.
The issue is that they're far more effective within their range than just about any other infantry weapon. Most things, even snipers, you'll have at least a second or two to react between first contact and death. With a scatmax, if you're inside its range and it sees you, you're almost certainly going to be dead if the player is at all competent. This is coming from both sides, incidentally, my main and my NC alt. The only way you have any sort of assurance of living is if he doesn't notice you or you're outside his range. Even with a single scat arm I could pop infantry at 10+m before they could react.
I'm okay with each faction's Max being specialized for a different role. I'm even okay with the VS Max being rubbish for everything but AA work. What I'm not okay with is when any faction has a unique tool that is specifically tailored to suit an environment that you have to fight in, which cannot be effectively countered with anything but weight of numbers or stupidity on the part of your opponent. It would be like giving VS a hitscan, no bullet drop, no damage reduction sniper rifle with a 1km max range, and then creating a set of bases which were crucial to the metagame and consisted of two towers surrounded by flat, empty plains.
I can take on NC maxes in biolab just fine. By "just fine" I mean that I can actually survive an encounter, escape, and sometimes even kill them (assuming they're alone, because running into max+5 guys is instant death and it's normal.).
The sniper-friendly situation would be far worse. Or not, because an airdrop would be the bane of sniper-filled towers. Or just take sunderers. It's a matter of using the right counter. Would you assume that infantry would rush head-in?
Have you ever played PS2?
That aside, you bring up a good point: there are hard counters for virtually everything. There are no hard counters for fighting a scatmax in a Biolab short of overwhelming population advantage. Either you have so many people that the Maxes can't kill you all, or you sneak around and try to pop them with C4, or you run away and hope someone else kills them.
How often are those "just fine" situations ones where you've got teammates supporting you? How often are they ones where the Biolab is empty and you're slowly nickel-and-diming the Max's health over the course of many minutes because you can't do anything in a straight fight?