General hero idea: Well, after Windrunner was added to Dota, i dont think a new archer is such a good and original idea. A Centaur is in Dota already, too, so imo your General hero idea is average.
Skill 1: Nice skill, though the damage will perhaps often miss, due to max range, that you cant easily predict sometimes.
Id make the missile speed a bit faster.
Skill 2: Cool skill, that would be really fun using it.
Skill 3: I dont see any similarities between this skill and Kotls Mana Leak, what did you mean with that?
Good skill imo, has very good synergies.
Ult: Good skill. This would be a reason to buy some MP-regen, perhaps a Perseverence at lvl 6. Then you can spam your skills and make this skill powerful. The low INT balances this skill out, so that it cant become oped. Great.
Skill 1 + Skill 2: Hmm, good, but Id prefer RacerKillers suggestion of giving skill 1 a stun instead of armor reduction. That would synergize better with skill 2.
Skill 1 + Skill 3: Good
Skill 1 + Skill 4: Spam to make Ult effective. Very good
Skill 2 + Skill 3: Great synergy.
Skill 2 + Ult: Great synergy
Skill 3 + Ult: Good.
Hero synergies: Rhasta + Sandata = GG
I like the synergies.
A perseverance in the beginning would be my first choice perhaps. After that Diffusials would be a good idea as well imo (nice Agi, Int and Purge to slow and make combo more powerful, though the Range of Purge is a bit small), SnY ofc, Orchid ftw, optionally Maelstrom or stygian Deso. Just listed some more ideas. Very good synergies imo.
Gameplay: To attack only from a long range would be wuite funny imo. I really like this gameplay.
Model/Icons: Heavens Tears icon is now Shackleshot. Id change it. 4/5
Overall: = 85/100 = 85% = Tup.
Imo a great hero. Fun and not too easy to use.