Excellent question and something that I am going through as well. I have no answer, but just some points.
1. With stocks, you have to follow several at a time. The reason i say this is because your setups that you are looking for might not happen all day long. Some stocks are hot for a few days and then volume and volatility drop. Also, each stock might have its own character, so although price action or how ever you are trading should work for all instruments, I think being familiar with the ebb and flow of each individual instrument would help.
2. When you are consistent, scaling up with stocks might be harder as buying more volume might not be possible without more and more slippage. With futures, it sounds like this isn't an issue. Sure you don't want to be trading 100 contracts of the ES, but I doubt anyone does that. As an individual trader, in CL for example, each penny move in price is worth $10. So just one contract can make you hundreds of dollar a day.
3. On the flip side, buying a lot of 100 shares and looking for a move of 25 cents really limits your risks. With the futures, each tick is a fairly high value tick, anywhere from about $5 for the NQ to $12.50 for the ES. So for starting out, it seems like stocks would cost less in terms of education.
4. Most of the experienced guys are trading futures. Two ways to look at that. You are trying to take money away from people who know what they are doing.. hence harder, but you also can follow along the expert advice of these guys. Trading random shares might not get you as indepth help as trading a popular futures contract.
That's what I can come up with off the top of my head!