What type of flies are you casting with this 12' 4# level leader? And what type of water? Can you place the fly on a paper plate 30' away from where you are standing? Inside a hula-hoop at 45'? If so, then more power to ya man!
Size #12, 14, and 16 royal wulffs -- size #14 sallies -- #14 beadhead brassies and a bobber at one point up above on the fly line >> leader loop.
Dry fly fishing is fun, but I intend to fish nymphs and soft hackles to rising fish more this year. The dries don't seem to take the bigger fish during a hatch, just like what I've experienced with bluegill (i.e. the most "dumb", smaller ones hit your foam beetles, the larger ones stay under and hit wet flies at their depth).
For casting, I doubt I was hitting more than 20-30' on the water the entire time I went out last time. I constantly cast in a field near my home using a couple of white towels and measuring tape. Putting the fly in a hula hoop at 45' isn't a problem at all, though I probably miss it slightly every few casts.
When I get to 60'+ I lost accuracy quite a bit, but can still get the fly in the ballpark.
I can hit 80' at maximum, and accuracy is really not there....making a cast at this distance pretty pointless for me for anything other than "gee whiz" value. I need more practice!
I'll be happy when I can hit 75' with accuracy and 100' without. Then I can go bonefishing!
Of course, I also like to use the water to cast -- sometimes at the end of fishing I"ll work a bit before heading home. I'm probably so used to using nothing but a level leader at this point I've become comfortable with it. Lately I've been working the roll cast pick-up to prep for my sinking tip use this spring on the shad run.
I really don't think that the taper of a leader has much of anything
to do with casting accuracy. You're really only affecting (supposedly) how the fly unrolls. If your cast is a ****-sandwich with a level leader, adding a hand-tied or store-bought tapered leader won't change anything.
Like I said - try it before you just assume popular opinion is the only way. Start with yarn, and then move onto weighted flies.