This is why I love UU. You can use nearly anything and be successful, and in my case I think I may have stumbled onto a metagame staple. Leafeon.
Now, Leafeon is often seen as a physical attacker and his stats reflect that, but I find his physical wall set is much,much,much more efficient.
Leafeon
name: Physical Wall
move 1: Wish
move 2: Protect
move 3: Yawn / Roar
move 4: Leaf Blade
item: Leftovers
nature: Impish
evs: 252 HP / 252 Def / 6 Spe
Why... is what I first thought. I mean smogon is filled with these. Those useless sets that some pokemon have that are either: outclass or just plain bad.
(Raichu in question has a choice Specs set when Manectric is faster, stronger AND has switcheroo)
Simple and straight EV's for maximum tanking ability. It's a fantastic counter to MANY physical attackers, and is more than capable of being a team player.
Wish is single handedly the one reason why you should use Leafeon over Tangrowth. Wish and Protect go together as one providing reliable healing and proper protection. Yawn is poor mans Sleep powder true. But it's reliable and I won't curse because it can't miss. Yawn and protect also go hand in hand.
I've had phenomenal success using Leafeon and many of my matches reflect that.
Now I haven't won many because my current team is a tad poor (Testing Raichu*)
but often times I can easily hold out with Leafeon alone due to it's sheer versatility. Yes, I have literally turned some potentially 6-0's to 2 or 1-0's with just Leafeon alone.
Furthermore, it makes a monstrous defense core with Registeel (Regileaf or Leafy steel) walling nearly all of UU save Moltres. (gotta pack bulky waters)
You guys should really use it.
Pros over Tangrowth:
*wish
*speedy
*Reliable (Tangrowth has to use both power whip and sleep powder, both moves have... shady accuracy)
Tangrowth
*Bulkier (lower defense but much higher HP makes it bulkier)
*Sleep powder can sleep switch in's.
*I haven't got much to say about Raichu, save that he makes a decent alternative to Raikou. For one he isn't hard walled by Chansey / Registeel. (2+ Focus Blast 2HKO's chansey and can OHKO Registeel with 1 layer of spikes)
It's not amazing and clearly inferior, but if Raikou ever goes to BL, you might as well use him!