I played at launch through about i7 (I think, definitely post CoV). Two big issues hit early scrappers, the reduction in the total bonus of secondary (defensive) abilities (was originally the same as tankers, not the 75% we have now) and ED. I had a DM/Invuln scrapper (back when Invincibility rooted you making TP the only viable travel ability) and could easily solo most AV missions (especially the werewolf and the claws scapper AV...don't remember their names). The other popular (AV soloing) build was Spines/Regen.
