The answer of this question depends on your opinion as to what the AHL should be.
If the AHL should be a league which allows nearby NHL fans to see "prospects" for a cheaper price, and also allows NHL teams to circumvent the salary cap by being able to do short-time call-ups, then the post where every AHL affiliate is in the same NHL city is the correct answer to this question.
I'm not sure that is best for hockey in the long run. Travel costs would be at the NHL level. Attendance would probably be spotty, with some markets doing OK, but others (San Jose, looking at you) pulling in 2-3k fans. The call-up thing is overblown too, because unless schedules align, it is very likely that either the NHL or AHL team would be on the road at any given time and far away from their affiliate.
The other vision is that the AHL is a league that develops prospects for the NHL team, with more emphasis on "development" and less on "call-up". In that case, it makes sense to have geographically tight groupings of teams to minimize time and expense spent traveling, and to put the teams in markets in those overall regions which will draw good levels of fans.
The AHL is in neither place right now. It currently is emphasizing "closeness", primarily for salary cap reasons. (It seems silly to realign minor league hockey instead of to tweak the rules on when salaries count towards the cap to not give teams that have their players nearby an edge.).
It is putting teams into markets that are both remote (Texas) and poor (Belleville).
The national footprint increases travel costs, but also importantly, creates big disparities between both revenue and attendance (Chicago being in the same league as Bridgeport)
The geographical expanse is creating effective geographic mini-leagues which are too small (Springfield only plays 13 of the 31 teams, playing Bridgeport, Hartford and Providence in almost half of their games).
I get the fact that people who aren't in-person AHL fans like this idea of a national "mini-NHL", but I really think that this "gotta put the AHL team within 30 minutes of the NHL team" thing is ruining the league and hockey in general.