Your suggestions do tamper with opening strategies.
1: That’s two less planes to hit Hunan. Without them, the J1 has been weakened a bit.
2: Now the Germans may be less willing to jam their submarine into the British DD/TT off of the coast of canada for that 50/50 chance. Part of the draw of this is knowing that it will be able to convoy U.K. if it wins, and knowing that the US can’t retaliate prevent it, even if there is a J1 DoW.
edit- Well, it’s a 40/20/40, so 40% chance to convoy, not 50%. Still.
3: This extra Indian sub affects something for sure. The 1/3 chance the Japanese cruiser has of surviving after killing the UK BB in SZ 37 can now be killed very cheaply, which also removes its ability to potentially convoy UK Pac. For the 2/3 chance that the cruiser does die, now the submarine can hit SZ 36, causing at least one boat less to be on the Philippines after a J1 to dissuade it from doing so, reducing your overall fleet mobility. And whatever happens with the cruiser, the sub can always hit 43, maybe further causing you to need to pull a boat off of the Philippines.
4: This only really affects a G1 Barbarossa, which isn’t super common, but still.
This is to say nothing for the long-term consequences of these additions. You only made the claim that these units don’t affect opening strategies_*_, and it seems to me that they clearly do affect them.
*I interpreted this to mean the combat moves on the first round of play.
So yeah, J1 is knocked two pegs down.
The G1 strategy, while already not the best, is reduced in its effectiveness as well, so you’re limiting Germany’s options of variety–something I don’t care to do since far too many games are G2/G3 Barbarossa in my opinion. Variety is the spice of life.