I think most of the test balloons in the OP are kind of off-base. And, I'm going to bracket lack of support b/c this is a product that came out towards the end of 3E's product life. And, a controversial one, to boot, for silly reasons, but nonetheless.
One actual flaw to me, which might be related to the lack of support, is just that the TOB designers were very ... let's say cautious, with what they allowed Maneuvers to do. Like, if you compare what a Maneuver of level X can do with spells of level X, even confining things to similar types of abilities (i.e., compare spells that grant attacks or deal damage to Maneuvers, rather than trying to evaluate how powerful Solid Fog and Slow are), the Maneuver's results end up being kind of tepid.
Part of this is undoubtedly do to having such a vast panoply of spells available that I can cherry-pick to find the best most awesome ones for whatever purpose I intend. But, it puts TOB characters in a weird spot.
Compared to "pure" "martial" characters, they are much more interesting to play. That's a big plus. On the other hand, given a reasonable amount of charopp, they often lag behind in major martial things, notably damage. Well-built Swift Hunters and Uberchargers and so on do way more damage than TOB characters. Although, yes, of course, some of those can be combined with TOB to greater and lesser degrees.
On the other hand, compared to a pure caster or even a gish, they tend to do less damage and have less versatility. I guess this last point is the one I should have led with: when considering a concept I often find some flavor of gish (including psi-gish) is often just so much better than the TOB build I had in mind. Which is a shame since I really like TOB.
