I am playing a Weapon Master in IH and having fun with it. He uses a Maul (2d6, x3 crit), and goes the Vorpal Hurricane (god I love that feat so much)/Power Attack/Weapon Focus route.
The higher BAB makes Power Attack more attractive, as when you go all out you can go more all out than anyone else. Of course, in IH critters tend to have lower ACs and higher DRs, so all out Power Attack is more useful.
The token abilities barely ever get used. You get one token per successful attack vs. your "target" (and if you change targets, you lose all unused tokens), and I just use it to add +1 to hit on the next attack, for which I will get one token, rinse and repeat. Really, they are so rarely used it is silly. I suppose a weapon master that went for two-weapon fighting and razor fiend might get more tokens that way, but even there one gets tokens that are mostly used in the next attack (or else you save up the tokens and risk wasting them if your target dies before you use them).
On the up side, in IH, they are the only class that can get to Feat Mastery 10 for some of the feat masteries, and thus they are ahead of the pack (I went the "Power" route and am ahead even of the Berserker, who will never get Feat Mastery 10).
I think the WM would suffer in the conversion to regular D&D. As you have written, they would have even fewer tokens, less BAB (for Power Attack maximum purposes), and I don't know what you think of allowing the Feat Mastery system. The skill groups for Athletics is nice, since by spending one skill point you get to increase ranks in Climb, Jump and Swim simultaneously (and they do have more skills and a higher average hit points than a regular fighter). They get a "defense" bonus, but i am not sure if they keep that in D&D (well they have a separate class "defense" bonus which would give them a small AC boost.
It would probably make sense to jettison the Weapon Tokens and replace them with bonus feats, or else give the WM more, not less, access to Weapon Tokens.
