Simple and Customize-able Wild Shape

Hey guys. One of my friends in my 4e game wants to play a Teen-Titans like Beast Boy druid, but was complaining about Wild Shape not offering any mechanical effect. So I thought about it for a minute and threw together this simple wild shape variant. The features and flaws are flavor-fully vague, making it easy to fit nearly any 'natural' animal into this system. It might not give specific abilities, but it's simple to use and easy to make a custom wild-shape mid-play. What do you guys think?

Wild Shape

As a full-round action you can take the form of a wild beast, change back into human form or change from one beast form to another. When you turn into an animal with wild shape, you pick an animal to take the shape of. Your base beast form is mechanically identical to your normal form. However, each time you enter a beast form you can choose two features of that beast form. The features of that animal form must make sense for the chosen animal. The available features are:
- You gain a flying, digging, climbing, or swimming speed equal to your normal movement speed.
- You gain a +1/2/3 power bonus to your AC, Fort, Ref, or Movement speed.
- You gain a +2/3/4 power bonus to your damage rolls.
- You gain a +3/5/7 power bonus bonus to acrobatics, athletics, perception, or stealth checks.
- You gain the ability to breathe underwater.
A single feature may be chosen up to two times. If two features of a wild shape each provide a power bonus to the same attribute, the bonuses stack.

In addition, you may take one of the following flaws as part of a wild shape. For each flaw your beast form has, you get an additional feature for that beast form. The flaw of that animal form must make sense for the chosen animal.
- You lose a movement mode you would normally have.
- You take a -3 penalty to AC, Fort or Ref.
- You take a -4 penalty to damage rolls.
- You lose the ability to breathe air.

At Level 11 you may take an additional flaw as part of your wild shape up to a maximum of 2 features and 2 flaws. For each flaw your wild shape has you may take an additional feature for that wild shape.

Examples
Level 11 Druid

Turtle Form -3 Ref, -4 to Damage Rolls, +4 AC, +2 Fort, Waterbreathing
Leopard Form -3 Fort, +3 to Damage Rolls, +4 Movement Speed
Crow Form -2 Fort, -4 to Damage Rolls, +2 Ref, +4 Movement Speed, Flight
Ant Form -8 to Damage Rolls, +5 Perception, +10 Stealth, Climbing

Your wild shape as you have it would give a lot of versatility that a lot of 4e classes just don't have. It's not necessarily power in the numbers way, but in the "I can do more stuff way." I could not, for example, writing a level 2 at-will utility power that says "You gain flight speed 6" or "You gain +4 speed." The best I would offer is to tie it to Daily attack powers (inspired from the Barbarian rages) or put these features as Daily utilities with an encounter duration.

Given that I know the player using this won't be prone to abusing these rules, I can still make this kind of monstrosity:

Oaken Form: +6 Damage
-Or-
Stone Form: +2 AC, +2 Fort

There's no reason our druid can't walk around in one of these forms all the time (and be an excellent off-tank). The full-round action to change would be crippling for a by-the-book druid, too. That said, I have a suggestion; keep Wild Shape the way it is for combat, but add a supplementary ritual with no component cost that allows several different animal forms that go away at the start of combat. Since the main worry of the alternate movement modes like permaflight is the unreachable artillery, this could work as a solution without having the balance issues a versatile system like this is bound to have. Also, there's no reason past level 10 not to have Wild Shape give Waterbreathing and a Swim speed at the cost of breathing air for free; Waterborn is a Nature ritual you'd get at around the same time. For the damage and defense related abilities though, there's a reason most special wild shapes require feats to provide combat bonuses (usually at epic tier, for some reason). Most of the difference between forms otherwise is fluff, otherwise. I don't think a system like this is absolutely unworkable though, it just adds versatility in a system where most characters are roughly as versatile as the next. For this campaign personally, I also don't think Flight would be broken as an option as long as it was not abused as artillery.