Scrappers have a higher damage cap of 500% because they are involved in melee but some scrappers (spines for instance) also have ranged attacks. Conversely, the blaster secondaries have a lot of melee range powers, not to mention Nova and Inferno which are point blank range primary powers. Why not make Blasters and Scrappers have the same damage cap but ranged attacks have a lower cap than melee attacks? So make Blaster Ranged and Scrapper Ranged attacks capped at 400% whereas Blaster Melee and Scrapper Melee are capped at 500%. This makes more sense because melee is much more dangerous for Blasters than it is for Scrappers and makes the situation more safe for a Blaster to rush in and use a quick melee or use a melee attack in defense when a mob gets to close. It might also make sense to have more Blaster secondary melee have a status effect for that reason (defense). For instance, make Fire Sword and Fire Sword Circle and maybe Combustion (debatable) have a chance to disorient who they hit.
Consume is very good by the way but it's one of the few really good powers in fire secondary. I have three attacks from my fire secondary. Consume, Build Up and Ring of Fire. Tried some of the rest and respeced them out at some point as they weren't worth it or weren't worth the risk.