Well Azumarril is even weaker and its still used more often (probably because of Aqua Jet). If Medicham had a base 100 attack then its attack could reach just under 600 without any boosts (besides Pure Power). That would ridiculous.
Azumarill's bulk is very good for NU/RU standard, so it can run a defensive set, also with huge power it can run offense while remaining decently bulky and with aqua jet it can bypass it's low speed. Medicham's on the other hand can't take attacks too well because of it's low defenses and have a mediocre speed at best bypassed by bullet punch... Sure it can punch harder than azumarill but azumarill last longer... I think if medicham had more speed or mach punch it would have been much better! Anyway, let's finish this debate by saying that sorry if I offended anyone... I knew my original post would draw a debate but I might have been carried away a little... So... sorry again!