well of course if it works for you then that's your choice and good luck to you..but the main 'problem' it seems that you have to me is that you're not checking the aggression numbers in front of you before you make your play...
you can see who are the passive WT and who are the aggressive ones at a glance surely - don't you have Vp$ip,PFR,PFA,WtSD , W$SD and hands played up for all players? same for Xtra-Loose
another problem with on-the-fly fixes to perceived problems is that the player categories you end up with will not be balanced...
the reason that the 9 standard categories come after the 5 priority ones is so that the unusual players are highlighted first
it also means that you can tweak/change/delete the five without messing with the balanced player base underneath..
sure UA and CS will always be aggressive and passive respectively - you could split XL, WT and SM into passive/aggressive/neutral if you had 6 more category slots but you can also get the same information by just looking at their PFA ratings..
and if you split these categories up to end up with too few in each so you would have to loosen their criteria to make them worthwhile again - throwing off all the other nos.
UA consists of less than 4% of the playerbase after 20 hands rated, yet you have dropped other categories to split them into 3? how is that a worthwhile 'fix'? and it looks from your figures as if all three types have the same win rates too..
you also seem to be under the misapprehension that WT players should be passives who never raise back- in fact WT players are players that don't see many showdowns- they will either fold or raise rather than call - passives tend to call more - so more often WT will be aggressives - but as they only go to showdown one in 7 times or less they are still worth bluffing at - if they re-raise you may have to let go especially if they have a high W$SD - but they aren't extreme aggressives like UA's so overall it's still worth doing - and those few that are very aggressive and somehow escape being rated UA you can just avoid bluffing if you like as you will see their big PFA's on screen ..
you are wrong that any WT players will be re-rated UA btw as UA's are rated first (no 4) and WT (no. 5)
if you want to run your amended rules on a decent sized DB and post the same table that I have on the new autorates page we might see how balanced they amended rules are , but I can't say I'm very hopeful..