Most Alt coins are completely pointless and just poor replicas of what's already out there with little to no improvement.

And none of them have offered anything in the way of major improvements over BTC.

isn't the Diff level / hash rate the only reason(s) peope mine them?

LTC is an exception, but there is profitability in new alts, pump and dump like FTC? pls tell me if i'm wrong?

I Concur - Altcoins are like penny stocks. A few succeed, the majority are worthless. That's what most day traders do to make a buck.