If you are after 3* ascension mats, then this revised AL does seem a bit better. If we run Recipe 10A, then each week we get: the 3* mat from Recipe 10A; and, then you can choose the 3* ascension mat from the shard exchange.
If you are after 4* ascension mats, then IMO the proposed revised AL is far, far worse than the current AL.
Current AL:
Having developed Level 10 of the AL, we can run 3 recipes in parallel. If you run Recipes 8, 9, and 10 in parallel, you will get, on average 1487.5 shards per week (=600 from Recipe 10 + 450 from Recipe 9 + 3.5 * 125 from Recipe 8). So, on average, you would be able to do a 10000 shard exchange every 7 weeks or so.
This means that every 7 weeks or so, in the current AL, you can get a GUARANTEED 4* mat from the shard exchange.
By running Recipe 9, you also have a 5% chance of obtaining a 4* mat.
Revised AL:
We can only run 1 Recipe at a time.
Recipe 10A no longer provides a chance at a 4* mat.
The shard rewards provides a chance at a 4* mat, not a guaranteed 4* mat.
Assume the drop rate for a 4* mat in the revised AL rewards is 5% and you opt not to purchase the shard boost from Recipe 10A. Then, in running Recipe 10A for 7 weeks (7 shard exchanges of 1000 shards each), you get essentially the same chance for the 4* mat as running Recipe 9 for 7 weeks within the current AL.
For me, I would prefer the current AL, where I have BOTH a chance at a 4* mat in Recipe 9 and have a GUARANTEED 4* mat waiting when I exchange the shards.