The bit I like about this is...
23 Credits - 5% Legendary, 10% Rare, 30% Uncommon, 55% Common
38 Credits - 15% Legendary, 35% Rare, 50% Uncommon
53 Credits - 35% Legendary, 55% Rare, 10% Uncommon
The increased odds of getting a really good item might merit an extra 15-30 credits.
The bits I don't like...
The lack of choice as to which type of item (attack/balance/defense).
The amount of items previously available has now been reduced by two thirds.
Without being able to select attack/defense/balance type someone wishing to for a high defense vehicle may have to wait until the next batch of crates to be released or maybe the one after than and by then they might not need it.
So with that said I can see why this idea was born, less of the artists time taken up creating items, the chance that people will spend a little extra to get the good items, and of course people not wanting to wait for the type of item they'd like are likely to buy the limited items that are offer so either way the revenue is still coming in.