The problem is that Smash's DLC is just a scam, and so far very underwhelming.
MK8 costs 60$, and the meat of the game is the tracks. half old, half new, 32 in total. You're paying 1.88$ per track. The DLC has 16 tracks, slightly more new then old, and costs 16$ if you're stupid, 12$ otherwise. .75$ per track is more then half the price of the original tracks, and more then makes up for lower amount of other content not added. (Characters, modes, ect.)
SSB4 costs... Let's say 100$. 50 (I believe) characters, mostly old and some new, are the main focus. 2$ a character sounds good. Mewtwo costs more then double a full character, 5$, and really isn't one himself since he lacks custom moves. He comes with nothing major to offset the 150% price increase. And to top it off, he's an old character with minimal changes compared to other returning characters and didn't really stand apart in the first place. Sure, you could of gotten him for free... But that wasn't an option for everybody. Lucas is going to be even worse since he's just a clone of Ness, and somehow I doubt he'll cost much less then Mewtwo if at all.