They use the shape but they're rarely the same. Probably the only ones that feel the same are Gameboy SP and original DS. Like, the original Classic Controller d-pad was pretty bad, but the Classic Controller Pro has a great d-pad. Both appear identical. Same with DSi to DSi XL. And size never really mattered to me. Best ever is the Saturn d-pad, which is pretty large. But Nintendo's best is still the Gameboy Micro, and Sony's best is the Vita. Those two are relatively tiny.
Anyway, Wii U Gamepad has a fine d-pad. Face button location is a bit uncomfortable since I'm not used to it yet. I have no reason to get used to it when I'm playing Mario with the Wii remote. Tablet is comfortable for what it is. Going back to the 360 controller, or hell, even the PS3 controller, you remember how much more comfortable those are.
And again the gamepad went from charged to dead in 3 hours (separate sessions over a few days without charging; level 3 brightness and power saving on). While I can't imagine a time I'll be playing for 3 hours straight, it's still a shame.