The size limit was what really made the WiiWare service suffer in the long run, Super Meat Boy was originally a WiiWare game that got canned because of the space limit.
That's not to say that there weren't some great games on the service, The Konami ReBirth Series, MegaMan9/10, Cavestory, World of Goo, Jett Rocket... and more recently we got La-Mulana on there, and hopefully Retro City Rampage is coming out later this year.
I never viewed the "minimum sell" as something bad really, your game has to be pretty shovel if it can't surpass that.
A real improvement I keep hearing though is the much better support Nintendo offers to eShop title developers, plus the process of getting their games on the service is waaay faster than before.
Another plus is the new focus on online and things like DLC/updates, something developers have really taken advantage of recently.It's easier now that you get informed about what software has been updated or has DLC available when entering the eShop.
As long as the Wii U continues what the 3DS started I see no reason why indie developers wouldn't choose to include a Wii U version of their multiplatform games.
The basic problem was that the performance and data storage restrictions of the Wii greatly limited your ambitions for the download service.
When Nintendo first conceived the Wii Ware service way back, they must have been thinking small, possibly smaller than DSiWare. They really underestimated what developers would plan for download titles, or what their needs would be.
Thankfully this appears to no longer be the case for the 3DS and Wii U eShops.
Look at how this has effected Sonic 4, episodes 1 and 2.
Episode 1 is technically unimpressive, all of the pre-rendered graphics and overall graphic design leaves much to be desired. Meanwhile Episode 2 does not exist on WiiWare as they allowed themselves to be more ambitious, actually designing a better game as a result. Admittedly though had they played it Nintendo's way and designed it old-fashioned like a Genesis title, rather than new-fashioned, it's possible both episodes could've ended up on WiiWare.
Odd little quirk about DSiWare on the 3DS, they're kept on a small NAND storage space the same way as on a DSi, there is a finite number of such titles you can store on a 3DS the same as on a DSi. They also have a pain of keeping save data attached to the game data and won't let you manage the save data separately unlike WiiWare.
This results in complications when you need to transfer DSiWare from one DSi system over to a 3DS, or simply move a game from system memory to SD card, at which point is simply to avoid re-downloading a game.
It's possible that such designs are measures against known save-data exploits that have been carried out through both the Wii and DSi, like Twilight Princess or EA's Sudoku title.
