Reminder: even if everything is "safe" on paper, Flawless block is going to make strings punishable either from the first hit or a gap in the string.
The flawless block is true, but mostly you will be blocking normally and attempting to “take your turn”.
The big thing in this game will be taking your go when an opponent is minus, this more than any other MK yet.
Like most NRS games, the characters with the best game when it’s their turn have always had a fast mid option when point blank. 8/9 is perfect, 10/11 is optimal.
When Sub is point blank and it’s “his turn”, even after his f4 (+4) his fastest mid is B3 (13 frames, or b4 sweep (12 frames), but if you vs an opponent with a 6 frame, they need to be -7 or worse, otherwise, nothing but a d1/d3 is guaranteed. So he will still be fighting for those moments...until an opponent respects your d1/d3, only then can you opt for f2 (14 frames) or B3 (14 frames), it won’t be a given.
He can poke, with d1 but he will lose his turn right away, so d3 will be your best poke, d4 will only give you advantage which you already had.