Here comes my thoughts about your previous arguments:
1st, it's the fact that Many small-capped forex firms got lost due to various misconduct/violations of regulations. With many clients left crying for their lost!!! Even they won the lawsuit, little money to claim back, as the firms are really poor and the bankruptcy law doesn't protect such forex clients with first place !!!
2nd, it's also the fact that, there are also some(not that many/at least some) Big-Capped forex firms have the records of Violating the Regulations of both NFA and CFTC!!!
For example, let's check in the following link to see Both:
One World Capital Group

example of Small-Capped)
http://www.nfa.futures.org/basicnet/Details.aspx?entityid=0359973&rn=Y
Forex Capital Market

example of Big-Capped)
http://www.nfa.futures.org/basicnet/Details.aspx?entityid=0308179&rn=Y
For the above 2 firms, no matter Small and Big, they both have violation history!!! For FXCM, it had more violations than One World CG, of coz, mostly due to its longer company history and much more no. of Clients being served!
My friend, if you have any doubts about any firm, just check in NFA
http://www.nfa.futures.org/basicnet/
Search the Regulatory History of it by the Name of the FX Firm,
then check its History of Operation first,
then check the Regulatory Actions against it thoroughly,
then check the NFA Arbitration Awards to see the Claims of Clients,
To my little research, of coz, we all know the fact that many small firms got the court orders to shut down directly!!! Real Nightmare!!
But, some Claims from Clients against those Bigger firms seem rather Unlikely to succeed at the end, although some other did!