Curry and Harden would have a shot (hah) against anyone, at least in theory, but I don't think they'd have enough size in the supporting cast to really contend.
The Warriors are a truly lilliputian team, especially if you take away Wiseman and Wiggins.
Looney and Oubre are 6'8'' / 6'9'' and they'd be the tallest guys in the rotation.
Like the Celtics.
Eh, I don't think it's really comparable.
The Celts have Brown and Tatum, for one thing, who are tall, athletic wings.
They also have Theis, Thompson, Williams, and Williams. Those guys are all under 6'10'' but they're generally pretty solid and have good length as well.
The Warriors aren't just small when you look at the starting lineup. Their bench is made up of guys like Wanamaker, Damion Lee, Bazemore, and 6'6'' Eric Paschall. It's just a small team.
They're not just undersized at the 5. They're undersized at virtually every position other than point guard. It's not just height, either. Most of those players are quite slight. Oubre, for example, may be 6'8'', but he's very thin. Paschall is the one exception to that, but he's about the same size as Grant Williams.