The PS4 will in no way share the struggles of the Wii U launch.
Sure, there aren't enough great games at launch, but that wasn't quite the Wii U's struggle.
When a NEXT GEN console launches, it's supposed to do so with NEXT GEN games. This is in terms of gameplay, but most especially in terms of the most obvious: graphics.
The Wii U did not do that. did it add a second screen, which is next-gen-ish. But the launch games (and launch window games) were nothing that couldn't be seen last gen. We had a Wii level 2D mario game, an xbox 360 alien game that got ported to Wii U, then became a zombi game exclusive at the last minute and looked like it, some third party ports of last gen games that looked like last gen games, and a minigame bundle called NintendoLand.
Nintendo didn't have the resources to get its big games out in time and third parties were content to forgo learning the new hardware and just port nasty old gen code to it.
Though things are changing now, that's how it was at launch.
The PS4 doesn't have that problem at launch. It is coming with games that have been developed for the ground up specifically for its hardware spec. It also has the benefit of third parties enthusiastically developing for it properly (made easier by its architectural similarity with one of its competitors, the X1).
Killzone looks fantastic and is an obvious NEXT GEN game when you see it. Drive Club has some kinks to work out, but it still looks like a proper next gen game. Destiny won't launch, but we've seen it and it is amazing on PS4. We didn't even have a glimpse into X, Mario 3DW, Mario Kart 8, etc. when Wii U launched.
And most third party games look pretty exciting and "next gen" on PS4.
So there won't be the "underpowered" misnomer confusion suffered by wii u. and there will be games actually meant for the ps4 specifically - something the wii u didn't have.
The PS4 won't suffer that fate. but there may be other challenges ahead.
The Wii U is getting stronger now that actual next gen games built for it specifically are out and coming out.
the wii U had a rough launch. but it recovered well and if current trends are any indication, the thing will sell like gangbusters with every major game release.
it takes Nintendo a little longer to get moving, but when they do, they are a force.