I agree with the OP. Please, please, fix targetting!

Assist should be of paramount priority right now! I would also like to ask for the return of the <bt>, <lastst>, <stnpc>, <stpc> and the addition of <stfoe> or equivalent. Treating NPCs and enemy mobs as a single category makes no sense.

Also, as it stands after patch 1.17, gamepad targetting still needs one more fix: Although the UP and DOWN arrows now do cycle party members in the party frame order, the corresponding member lacks adequate highlighting on said party frame. This causes the need to keep your eyes on the TARGET frame, as it cycles from member to member, a frankly undesirable distraction. I can't begin to tell you the amount of accidental aggro I have caught since the patch went live. If I want to be mindful both of my party-mates HP levels, and of targeting them quickly so that they can be cured in a timely fashion, then I can't afford to mind my surroundings.

Highlight the party member that is being subtargetted after the spell has been selected, please!

The issue with the Function keys is also overdue for a fix. It made sense to reserve keys for other purposes when parties were 15 members, but with 8, there're more than enough to assign one key per party member. Either F9 or F12 could become the key for mobs.

R