Why MinMax when you can max out everything without cheating?
Minmaxing is entirely different from cheating. When you say "this option looks better than that option", that's minmaxing. "Oh man, the Toughness feat looks like it really sucks, I'd better not take that" is minmaxing. "I think I'll find
fireball more useful than
lightning bolt" is minmaxing.
Any decision between two things is minmaxing. It is unavoidable as a player unless you're actively trying to make yourself suck, and it's unavoidable as a designer because it's impossible to perfectly balance every option.
What you
can do as a designer is control how much better X is than Y most of the time, and in this regard TiTS is actually fairly decently designed. You can clear every challenge as every class without too much more difficulty in one than the others, discounting the period where Tech Specialists were gimped by the lack of good energy weapons. Mercs are generally better than the other options, and ranged mercs are better than melee mercs, but you're not suffering for not picking that option.
Similarly, you
can max out all your stats, but this doesn't make strong builds particularly stronger. Stats are capped, and as long as you have 40 Aim and all the range perks your merc is going to steamroll everything regardless of how many points he has in any other stat. It
does, however, make what would otherwise be cripplingly weak builds much more viable.
In fact, I would argue that removing stat training would make the game
less balanced rather than more. It actively penalizes melee characters, who need Aim to hit things in addition to Physique to do damage, and even more so characters who don't make optimal class feature choices, while having no real impact on characters who build optimally.
