AFAIK most, if not all, buffs are either self-buffs or party buffs. Don't know for the old server, since i haven't been playing there for over a year.
Soloing isn't easy, but Giants seem to do fine on their own at the moment (Origin).
Archers too, if you kite enough.
Partying seems the key, though. On Origin that's not really an issue, plenty of people around. Old servers may be dead though, but they have been already so for years.
Isen is the server without epics, but that does not necessarily mean it's for beginners - I also think it has the lowest population of the two old servers.
As for builds: you can choose to go full STR or 3STR1VIT depending on your gear, RPs and patience. One will do more dmg, the other will survive longer in weaker gears.
Most of the OG's currently on forum/ingame only came back for Origins and have little to no interest in the older servers anymore. At least, I don't and I wouldn't be here at all if it weren't for Origins.