I would like it to be possible to have the original icon of the primary spell set to the macro as I sometimes prefer the original spells icon over the one of the macro's. Also as something of a little bit greedy, I would like to set targets for any spells, as I would like to set the target of Manaflow to myself for my coercer but can't under the current macro builder..
Actually, you can. Right-click on the spell on your hotbar and choose 'create macro'. It creates a macro with the spell as the primary and uses the spells icon for the macro.
Both are possible. You can use any ability/spell icon for any macro. Just drag the icon you want out of your knowledge book, and onto the macro icon in the macro editor. For most spells, you can set a target. For example, put Manaward in there, and you'll see a box in which you can type a target name. Mana Flow is odd, since it's target is tagged as Other (AE). But you can use the command /useabilityonplayer in the macro to get the job done. /useabilityonplayer Ynnek Peaceful Link /useabilityonplayer Neverready Mana Flow etc... Edit: (I don't remember if you use the slash when putting commands in the macro editor. Probably not.)
