I like tribal and it's something I'd like to see support for. It can be tough to design around though. Some of the issues -
The regular "3 mana lord that grants +1/+1" can't just be applied to every tribe and every strategy, since that kind of effect is strongest when you can get out a large number of creatures. It works for tribes that have lots of one drops or have spells that make token creatures and where the main path to victory is attacking.
There might be some other tribes that like getting a p/t boost, but because their creatures are more expensive mana wise, you are not going to get as many out in a short time so the boost needs to be bigger.
Vampire Nocturnus is a good example. But for some others, like
Sunrise Sovereign and
Crucible of Fire, even the bigger boost wasn't worth it if you were only going to get out one or two creatures of that type if you were lucky.
But some tribes run even fewer creatures, or their strategy is something other than attacking, and completely different tribal effects are needed.
Like the resilient
Gravecrawler. You don't have to run as many zombies as possible to maximize its power, but you need a few in your deck.
Or the merfolk milling strategy based on
Drowner of Secrets.
Some tribes only really work in Limited because you have more time to mix and match the different effects. In Constructed, you're never going to run any of those six mana Treefolk that only trigger when you cast another treefolk afterwards.
Perhaps tribes need to be a bit more like Slivers - not just the lord buffing the rank and file, but the rank and file having tribal effects too. There have been some pretty unique effects like
Elvish Eulogist.