Well, I can't say I disagree. Bassists need to be more persistent and clever in order to get these goodies sitting properly for bass guitar. I wouldn't get too depressed being bummed out that there isn't much bass love here in FAS land. I've been there, and it doesn't get you anywhere. To the contrary, if you can demonstrate excellence in creating tones of any kind, it is usually met with recognition on the forum, and even by the FAS powers that be...so don't give up.
[edit: just saw this is FX8...apologies!] If you have the time, $$ and inclination, I'd recommend the ML Sound Labs 4x10 Ultra Res cab pack (11?), and the Ownhammer 4x10 IRs (needs Cab Lab to convert to AxeFx format). They can be the last bit that puts your tones over the top.
As a previous Sans Amp BDDI owner (sold my main and backup units), I can understand that a BDDI drive/amp model would be cool, as it is a familiar place for many bassists to live, tone wise. However, I've found that the more I've used the AxeFx, the less desirable the BDDI sounds have become. Over time, I've become much happier with the amp/cab emulations in the AxeFxII by comparison.
I had good luck with the Rat distortion in parallel, with the low filter set above 400hz or so, to keep it from getting muddy. From there, you can get it as fuzzy or gritty as you like depending on how much drive you dial in, and by tweaking the tone parameter. Parallel seems to be the key, though.
As for the wah, experiment instead with putting the wah block in parallel (again), and with fairly aggressive settings, blended to taste...OR...try using a Filter block with an expression pedal assigned to sweep the frequency, dabbling with the Q to taste. You might like it better. I agree, though, that the low and high frequency ranges of the wah block need to be adjusted lower to accommodate the sweet spot of the bass...low freq doesn't go low enough, if I recall correctly.
At the same time, I' don't think that it would kill FAS to spend a little time making some decent bass amp starting point presets. We can wish, can't we?