It's not the huge AS boost that is strong. It's while other AD's will have to build AS to compensate for their lack of a nunu support the one with nunu will build straight damage giving them the edge in farming, poke, pushing, and fighting.

AD's SHOULD be building damage first anyway. AS is late game, way after laning phase has ended. AD's that build AS beyond zerker greaves are doing nothing fast. THAT'S why Nunu is a bad support, the only thing he's good for isn't useful until after laning phase.

PBE and Caitlyn makes your statement seem a bit out of touch.

PBE is PBE and is trollish. The only ADC that can effectively scale with AS early on is Kog'Maw.

There are junglers that get the job done better than nunu. Has better sustain and gank power. Support nunu. Has better zoning, has one of the best buffs to an ADC. He's a best support

He's a terribad support and I've already been saying why. He's a glorified item that gets outperformed by just about every other support. So he has the same problem jungle Nunu has apparently? One thing he does bring to jungling is an effective double smite.

But he's also outclassed as a jungler. You're telling me you'd choose jungle nunu over someone like lee sin/ammumu? Let's compare.
Lee sin- Land Q jump to target, get your combo off
Ammumu- bandage toss- stun use your kit
Nunu has 1 source of damage output which is his E. Which is his slow. That's it. Now as support nunu you're offering better team comp. His E does a fair amount of damage. His spammable W gives AS which is essential to ADC lol.

I would because his E and ult do NO damage as support. He brings actual damage as a jungler and the slow can be used to gank. Not to mention he STILL has his W for the ADC freeing up the support slot for a REAL support.

Okay, I'll disagree with the original OP, but I'm well aware of the power of Nunu support (Gosu Pepper + Genja Nunu/Ashe lane). Give great MS and AS to your carry and they gain great kiting power in simply firing a shot and running away.

If you've ever seen Genja play Ashe, he'd often rush Zeal and a couple Doran's blades for simple ability to kite the **** out of his opponents. Building AS during the laning phase is viable if you know how to use it. Given the fact that many players simply don't know how to properly use it, I can understand your opinion.

However, you did touch upon something very important: Nunu is a lategame support. He tanks and powers up ADs such as Kog'Maw or Vayne and turns them into monsters without heavy AS investment on their parts. He slows down the AS of the enemy ADC and bruiser, plus draws CC using a great big AoE slow. He's by no means weak, but he does rely on getting levels and items (and his ADC getting them) to really shine.

What elo are you playing at? Nunu is good, but not OP.