This is not some evaluation of Tiers as you may have thought, or some complaint about them, it's a discussion on this idea of what can be done about Tier difficulty (Can be changed to be put into Suggestions, if needed).

Honestly, I think the way you have the Tiers set up is unforgiving to any player who has never done the Tier they're going to, sure they can just practice till they get better there but, using a lot of energy in the process, and it's unintended to use energy solely for training when going to a new Tier, right?

The jump in difficulty level between the Tiers is a bit too much, in my opinion, you don't need to lower the difficulty but perhaps try something like what I say below.

So here's what I think can be done, opinions can be said and other idea's can be discussed:

Instead of 3 Tiers, why not 5 Tiers?

That way, every time you become fully one type of star (Like, fully 2*, 3*, 4*, 5*) you'll be eligible to go to a new Tier. The difficulty for each Tier would be increased from the last, but not a huge jump like Tier 1 to Tier 2, or the even bigger jump, Tier 2 to Tier 3. You wouldn't have to become suddenly much better all of a sudden, but increasingly better as you become higher in Tiers, I think this way you'll sort of know what to expect in difficulty level from going one Tier to the next.

And to keep the Tier difficulty of the already existing Tiers, why not (If you make 5 Tiers), give Tier 1 the current Tier 1's difficulty, Tier 3 the current Tier 2's difficulty, and Tier 5 the current Tier 3's difficulty. Also, seeing as how if you were only 0* you wouldn't be able to do any Tiers, you would probably want to make Tier 1 accessed from 0* and 1* items.

So, any thoughts on this idea? I admit this idea may not be completely ready to be taken out of the oven yet, but it's just a start.