I don't mind playing in a seven card fit with say, AKxx opposite Qxx. There is a danger that I'll lose control because of the shortness of the suit, but having three top tricks and a chance at a long or ruffing trick for the fourth small trump represents compensation. On the other hand, I do mind playing with say, Qxxx opposite Jxx.
The other issue is that while 26 points is ordinarily enough to make a major suit game with eight trumps, it requires 28-29 with only seven.
So if there is likely to be a seven card suit, e.g. when an opener raises a major suit opposite a responding "one over one" bid or negative double with four cards, how do bidders deal with this issue? My understanding, for instance, is that openers will need Qxx or better to raise, not just xxx. Do the bidders make other adjustments to assure two or three top honors in suit between them? And what about the higher point requirement?
Or is one factor in the unpopularity of seven card fits due to the fact that there are "few" established bidding methods for them?