Just using SR as an example of how much power Primeape should have, but doesn't. However, that is without an LO or CB and against a mammoth 120 defense, Primeape does adequately enough.
I hate Lucario, don't ask why.
I also hate Heatran and the only way I would use it is if I used Magma Storm. For originality, utility, surprise, and why-not factors. I do not consider relying on the 70% accuracy as being a person who try's by luck or hax. To me, all Fire Blast has going for it is the awesome animation of shooting a burning poorly drawn stick figure IMO.
Also, thought of another strategy. How about Mew and Giratina(forme doesn't matter, but Altered for me because I like defense)as leads with Mew having MAX attack and explosion. Depending on the opponents pokemon, you can open up with explosion, attack with something else, protect(for scouting), helping hand(maybe better for Origin Forme), or just switch. Mew is just awesome and has lots of options to stick on with explosion.