My favorites are Azami and Nezahal, Azami for its classic status, Nezahal being a weird Voltron.

My recommendations (but only as as someone who plays casual and cEDH and rarely inbetween): what scale of combo or control do you want to go on?

On the control end, you could be extreme and build Baral, Chief of Compliance or Baral, Chief of Compliance and just say princess bride quotes. It's tempting to just counter everything and either pull a combo or build up Baral to Commander damage. I've had a Baral player counter 5 spells in a row, letting someone else win just because they ran out of counter spells. However, in competitive it's just a tad slow.

On the combo end, there's quite a few. Orvar has weird combos with twitch. Urza is the classic that has infinite Mana and stupid synergy with Orbs like Winter Orb. Azami, Lady of Scrolls just because I'm an old player and enjoy the classics. You can just draw a lot.

My opinion is that blue is not the best competitive color only because it's too slow and control isn't as viable in multiplayer. it also tends not to be budget friendly.

Were it to have something like vigilance and pseudo evasion like menace, maybe.

You'll have to build up to it to make it good (add Removal, double strike, etc), and with the buildups necessary, you'd be better off just just doing other aggros strategies.

Even in non Commander legacy formats like Canadian Highlander, it's far too slow or gives such a poor advantage.

In general, I like Commander's Sphere simply for decks that can use the draw and the sacrifice. It even still makes sense in competitive Dargo, the Shipwrecker for that purpose.