Tony Vargas
Legend
Loving to make unrestrained use of unrestrained buffing is certainly one example of not having a problem with it. ;PI know about CoDzilla, I still don’t accept that D&D was not a fine game before the 5e concentration mechanic. 3e/3.5/Pathfinder without this mechanic has been successful. I know people who still primarily play it without experiencing a problem with unrestrained buffing.
Seriously, though, 5e's BA mandate took such things off the table, entirely. Not so much fixing a problem with 3e as preemptively fixing what would have been untenable in 5e, because BA just couldn't provide the design space for it.
Concentration may seem like kinda a mordenkrad solution to a flyswatter problem, but it certainly works. The other alternative would have been to just not have spells, stack, period. Put two friendly spells on someone, the first one goes away. That kinda thing.
Older versions also had concentration (1e conjure elemental sticks out in my mind, for instance. A number of other spells had durations of 'concentration,' sometimes with a bit of duration following that). And, there was no check or save to avoid having concentration broken.This was a major limitation that no longer applies. So just because older versions did not have concentration does not mean they did not have other limitations.