I have both Deadpool and Nova at 12 covers each, and in both limited vaults the cover option is the one color I already have at 5 covers. If you give me the option to re-roll the vault to get a different color cover, then I’d gladly spend money on these pulls. Currently they are useless to me. You have someone wanting to spend on pulling for these and not being able to. You let us re-roll the other vaults, but not these. Please give us a break here.
Two things…
- A re-roll means a 1/3 chance of again getting the same color. So there’s that possible frustration.
- Anyone who really wanted to complete a 4 could use the re-roll to get all covers. Even starting from scratch. This would be a very different distribution of 4’s…other vault rerolls may keep a 4, but the vaults are much bigger and odds are lower of the desired outcome.
So, it seems very unlikely to allow re-rolls. FYI, I have been frustrated too. My XFDP is 5/2/3…the first vault was very annoying.
They are building the code. They could write it so that re-roll only works if you haven’t purchased any yet and they could do is so that it only rerolls 1 of 2 colors not already resented. These could make them too challenging to do, but it’s possible.
Also they could just make the reroll free, but only allow it before your first purchase. Then even if there was a 33% of the same cover, you could hit it 6 times until you got the cover you needed. This seems like it would be pretty simple to do vs my suggestion above.
Either way I agree with OP they need an option to reroll if they want to get the most out of these. I’d have bought at least 1 of today’s had it been a cover for Nova I could have used, but it was not…
Which is why Colorless covers needs to happen! Enough of the 15/2/3 builds already!
Or covers that don’t expire.
They should allow this for VIP members at least. If I let my VIP membership expire, well so do the covers!
Give VIP members a Comic Storage Bin! 
at least the hulbuster vault isn’t just the first power (the other ones were)
Another solution other than allowing rerolls or colorless covers. Program the vault to look at the 4* in question and pick a color you can use. Since they are trying to get us to buy these, it’s in their best interest to present something inciting.
My 5/5/2 HB still isn’t happy.