ok. personally, i think some mechs have two good weapon.
for example assault. it extremely good with AR, if you have good aim. at the same time, vulcan decrease your maneveurbality (fuzzy bunny this! it is impossible writing this word correct without translator), but can exterminate C-class very fast.
Also, i always go with SMC, because SMC funny and working much more good if you nub with 30% aim percentage in statictic.
but anyway, i try.
Brawler - SA, Flak
Grenadier - Vulcan (biut sometimes RevGL can be super good)
Cupcake - MFlak (and SMC if you nub)
Incinerator - papa
G2-Raider - lol. T32. It is obviously
Assault/TV - SMC, AR
Raider - reflak35
Bruiser - Vulcan
Predator - Breacher
SS - Slug
Scout - Flak
Infil - Heat, EOC
Bers - SMC
ripper - Slug
tech - RPR
...did i miss something?
oh, sure, i forgot rocketeer. best rocketer weapon - Heat and EOC. and don't tell me that i'm wrong! xD