I actually think DMC4 was a damn fine game, though I can understand why many hardcore fans found it disappointing after the (arguably) superior DMC3. For some people - myself included - DMC3 was a little bit too hard though, which made me like DMC4 a whole lot more. I could actually finish the damn thing. I am too old and busy to sit around perfecting my skills in video games for hours on end, so DMC4 was perfect for me.
My only problem with DMC4 is that it actually felt a little dated, even when it was new. Not much has evolved since the very first game. So, in all honesty, I can understand why Capcom would choose to reboot this baby. I fear they're making it worse though, for the sake of "modernizing" it. Time will tell.