Are you kidding. DLC has been one of the best additions to consoles this gen. And games like Smash Bros Brawl or Pokemon Battle Revolution should have had it long ago.
Nintendo also thinks like OP and that every game they release should be perfect. But that's not always the case, with bugs or broken characters and more. And even taking that into account, DLC is not this evil thing that brings down production values. Look at a game like Red Dead Redemption. It had a 50 hour main game and TONS of content. Then it just had 5 additional free DLC packs added later to expand multiplayer options.
I for one hope the next Nintendo system has an option for DLC. Smash Bros Brawl would have been one of the best games this gen if it had additional levels/level editor options for DLC.
Six upcoming games you should look into:
