At least in Commander he'll be restricted by only playing one of each of those lands, but you can also rely on getting Jodah out on turn four and keeping him out, so I suspect it's a wash, basically
Can I sell non-English cards
He later evolved into Infernape in Fighting Ire with Fire
Though Omarthis will only gain a single +1/+1 counter whenever another colorless creature gets any, be they one counter or many in a single instance, if we instead go-wide and hand out a +1/+1 counter to a whole bunch of creatures, Omarthis will get one for each, piling counters up quickly
A notable strategy involves using it in combination with Kaalia of the Vast Commander decks, where you can put Avacyn into play without paying its mana cost, immediately providing indestructibility to all your permanents