In any case, the original Arcane Archer sucked because of 3 reasons:
1. The only class feature worth worrying about came at level 2
2. Required spellcasting to enter, but didn't advance it
3. Crappy prerequisites and a ton of them.
You've managed to completely remove 2 and 3 and also gave a good capstone ability. I would, however, possibly look into some class features that weren't just money savers. As it is, though, I would play it. The ability to turn any targeted spell into possibly hitting a foe 20 times is rather juicy.
Also, people buy +1 weapons with a bunch of properties because it's just better that way. Unless I know I can't get a Greater Magic Weapon each day, I never go higher with one possible exception. Since MIC came out, I might get a +3 weapon for the Greater weapon crystals.
|Maybe something like traveling with the arrow? That could be a unique class feature. Alternatively, seeing things as though you were the arrow.|
Imbue Arrow: Which spells are allowed needs to be much more clearly defined, and how they work. You'd probably want to stick to very very specific uses, like the original wording and maybe touch spells.
Area spells (target is new center or point-of-origin of the area) but limit to specific shapes so you DON'T get someone trying to shoot a target with an Antimagic Field.
Touch spells (target is spell's primary target, follow original spell's rules for any subsequent or additional targets). The word 'touch spell' is nonspecific enough to still allow you to put Disintegrate on this.
|Seeker Arrow: Specify that you must be able to determine your target's location (correct square, if nothing else).|
|Split Arrow: Playtest, fine, but my gut feel is 'No,' simply because anyone else is shelling out a minimum of 32,000 gp for this. Perhaps limit to a number of times each day or each encounter, or require investment like your Swift action.|
|Arrow of Death: Save DC based on half of your BAB? Dude, that's crazy. 10 + class level + spellcasting mod is what I'd recommend.|
|Improved Imbue Arrow: You...uh...might want to limit what spells can go into this. Even if you're going to cap it at 3rd-level arcane spells, I will totally load up on Vampiric Touch just to ensure a half-dozen targets eat 10d6 of damage and I get half of it back in temp HP.|