This has no correlation to the guide in itself, it's a solid guide - a bit too walloftexty at points - but I wonder: AP Sona, ever tried it? Her heals drastically pick up in damage, and Sheen into Lich Bane and you're all set to damage, kill and kite like a beast.

I'd like to hear your opinion, but +1 nonetheless. Keep it up!

~Emo.

Getting Ionian Boots of Lucidity in my opinion is MUCH MUCH MUCH BETTER than getting Mercury Threads for Sona. The CDR is amazing. Also, your skill order isn't very well-set up. I'd rather have Sona's "w" maxed out first because that skill IS THE BOMB IN EARLLY GAME. Provides great sustain and all. Maxing "q" first isn't really that great of an idea, but it is good to max it after "w".

Also describe why you get Mercury's Treads instead of Ionian Boots of Lucidity
For me Having 40% of Cdr is way better than reducing CC's time.

There's some solid advice in here, but I think a few of the items need a bit more explanation as to why you think they're so important. Locket and Soul Shroud just aren't very powerful items especially compared to Aegis, which you've sort of shoved aside in favor of them. Aegis gives you and everyone around you armor, magic resist and a paltry damage buff. Locket gives armor to you only and a mere 15 regen to everyone in the area; the shield is only useful early game or if you're not a few levels behind (and as support, that scenario is pretty common). Soul Shroud only gives 10% CDR, compared to the typical 15% or more you enjoy from the better support items (Shurelya's, Zeke's, FH etc) and the mana regen is lost on anyone who doesn't use mana, making it an unreliable item at best. I'm just curious as to why these items take priority for you.