For starters, your mana hurts moderately less, with only additional copies of Hashep Oasis causing potential problems
Also, the lifegain hardly ever matters in a format like Commander, making it largely null in most cases, especially when small utility creatures are targeted
I think Overlord is the best due to its flexibility, but if you want more options, Wood Elves, Farhaven Elf, and Topiary Stomper are all quite reasonable
As a three-color planeswalker, Sarkhan is a good pick for your Dragon deck, especially since it can produce Dragons for a relatively cheap loyalty cost of just two counters
All variations of trilands Ive ever seen have been format staples during their lifespan, but the format being 3 years instead of 2 expands the options for multi-colored lands so widely and creates so many options for aggressive strategies that drawing a land that enters tapped can be a hindrance
That means if someone casts a ten-mana spell, they are going to be milling ten cards on their next untap step
