The shortening of 2703 along with the annulling of 2017 are both inconvenient. I usually take 611 or 613, and if I do take 613, about half the time I'm able to make an across the platform transfer at Hicksville to 2703 if 613 is on time and 2703 is a few minutes behind. Shaves about 5 minutes off my trip. I also usually make a connection to 613 at Jamaica if I take 2025 (7:32 Ronk due in Penn at 8:47). So now I avoid taking 2021 if I want to go on the Ronkonkoma branch since i imagine a lot of 2017's passengers will show up there and will probably resort to sticking to 611 when I go to on the Port Jeff branch.
Terminating 611 at Huntington would cause an uproar and would burden the super express from Huntington to Penn that leaves 5 minutes after it, though adding a Jamaica stop wouldn't be bad. 611 probably ha more than 70% load and 613 gets pretty close too. Just observations from riding those trains daily.
The one upside: the shortening of 507 means that when I do take 611, 507 won't hold us up getting to Hunterspoint. You win some you lose some, but the sooner this is over the better.