Light Shan (Shan)

Good Gods... I got this guy from this month's L&D scroll from TOA. Holy Smokes, he is Unholy... His S3 hits all the enemies with a stun (80% chance- 100% when fully skilled), bumps up the ATK BARs of allies by 25% and further increases their ATK SPD for 2T. It's like having a Bernard that can kick an A**. Swift is the only way to go- you want him as fast as freakin' possible (his S2 scales off ATK SPD and does a ton of damage). He can farm, do TOA, dungeons, PVP etc. 

Furthermore, once I put him on AD I could almost hear the crickets chirping Sunday as folks passed over my AD. I think I got hit twice... and one of them was a successful defense. I think I have a new MVP.

I don't really want to disappoint you, but Shan is hardly useful in late game unless you can get another couple of light nat5s than can use his leaderskill like Artamiel or Nigong in example. From C2 and up, most if the monsters are will runed, turning the 3rd skill useless in the first turn, so you'll have to rely on your Squall at first. Also if you don't use him as leader, he will be too squishy to be a real threat in defense, just like Taor or Lagmaron. You wont see any of them in c2 defenses and up. And in GW is more the same. Lots of will runed monsters and lots if speed teams with Chloe or Woosa that will ruin Shan's S3.
Don't take me wrong, hes's a very nice monster to have, but its far from being a game changer, and even within the Chimeras he can't be compared with Rakan or Zeratu that are top tier nat5s.
And sadly, Shan's Squall is not as useful as his cousins one due to the elemental neutrality. Lag can easily oneshot water monsters, Taor can do the same with fire ones, both are common enemies. Shan can only take advantage of his squall vs dark monsters wich are much more rare to face.
So you may need a very specific team of monsters to make him shine: a good speed leader, a def breaker and maybe an AoE stripper just in case all enemies are will runed.
Hopefully you can develop a battle strategy for him once you reach conqueror2 arena level and tell us wich is the best way to use him

You offer very good criticism and the points you make are certainly correct. He really needs to go right behind a stripper- instead of being the only SPD lead, which I discovered when I made a cleave team around him. Like any critter, he's only as strong as his support. I've found his S3 Stun to a very effective follow-up to Chiwu's AOE strip- if they don't have immunity, chances are they are stunned- I can't wait to see how effective it is once he's fully skilled. He's perfect for disrupting a speed tuned combo for this reason. He definitely needs a good tag-team partner that can do some damage- I run him alongside Lagmoran (with Chiwu as lead) in GW offense and between the two of them, somebody is stunned or dead on the first turn. He's a little more "niche" than I thought he would be, but still a great critter to have in the bag o' tools. I have yet to make a serious push in the arena- simply because I hate it. I'll defer to you for opinions on C1 or above.

Update: Shan is literally a God in TOAH. His S3 stuns without actually contacting the enemy, so he avoids revenge(s) and critters that inflict retributive damage (like Jultan). Being a Light mon, he does not glance against any other element, so the chance of his Stun landing are always good. Plus, he speeds up the team when he stuns the enemy, and buffs their atk bars by 25%. His S2 is a very formidable strike and is enhanced by his SPD buff.