I'll give the edge to Tarkir, mostly because at the time I was bummed out that I missed out on Kamigawa, and Shards of Alara seemed really cool as a three color set, so Tarkir was like a combination of aesthetics and concepts that I missed out on
Sapphire depicts intellectual, inventive, and creative souls, such as Aurora, Judy Hopps, and Hades
Effective +3/+1 and trample is a strong boost for just 1 mana, and most of it sticks around from the Monster role token it produces
Back Bahamut, Warden of Light (As this saga enters and after your draw step, add a lore counter.) I, II - Wings of Light - Put a +1/+1 counter on each other creature you control
Of course, there is no shortage of such decks, with Animar, Soul of Elements, Halana and Alena, Partners, and the new Chishiro, the Shattered Blade all being quite good choices for a red commander that benefits from +1/+1 counters
Its also a vampire and cleric, which are both popular typal themes