I would call that a good build because you have the right balance between the gpu and cpu for gaming. Though with Minecraft, and especially mods like FTB. You're going to want a better cpu.
My brother used to play FTB and he could get as low as 30-40fps, he had a i7 3770K. Which is much more powerfull than the i5-4430. Though you can always go down in render distance go get decent performance.
But since it's ONLY really going to be in minecraft that your games will benefit from a faster gpu, you should probably not change a lot.
IF you play alot of Minecraft, then consider the i5-4570 or i5-4670, and get the R9 270 gpu, it's still going to perform very nicely in games, and the added cpu horsepower is always usefull when you're not playing games.
then my cpu is weird because I have a E5300 and get get 30-40 fps with everything set to high until I messed with the minecraft files and something in the registry,