Unit/Ability/Item Ideas For CTF-like Map

i'm in the process of creating a capture-the-flag type map. there is a main item that you need to capture an # amount of times but it spawns out in the arena instead of you having to capture it from your enemies and everyone has an FFA to try and get it. i'm just looking for suggestions for units/abilities/items that youguys might think would be cool in this map (a ctf-like map). Some items will be sold in shops also. i have a lot of ideas for units but here are the definite ones that will be in the map so far:

Runner (Only unit that can pick up the "flag" and score points with it. 1 mana drained per second, dies when mana reaches 0)
Abilities:
-- Inner Spirit: (50 mana) Increases Movement speed of the runner by 75% for 12 seconds
-- Absorb Mana: (0 mana) Same as destroyer's ability.
-- Siphon Mana: (10 mana, creep version)

Guard (protects your goal. when you capture a "flag", one appears in your goal. it can be stolen by enemy units so the purpose of this unit is to protect the goal. also, it cannot leave the goal area)
Abilities:
-- Ethereal Imprisonment: (? mana) stops targeted unit for 6/8/10 seconds (like entangling roots without the damage/second)

so yeah, thats the basics of what i have so far, i have some more unit/ability ideas myself.. but who better to ask than the people who will play the map and give me feedback! tell me what youguys think and feedback is much appreciated. thx guys.

so what? no one has any ideas? i cant believe that... help me out guys! :-P