Scout, in my opinion, was a bit of a disappointment. It was meant to allow you to scout ahead and take out enemies in advance, but the pitifully small range it gave you and the fact that you got knocked out of Scout mode if you got attacked (which, in BioShock 2, was about once every twenty seconds) made it almost completely useless. My upgrade tree is made to (hopefully) fix its problems as well as make it both more useful and interesting.
Changes: If the player's body is attacked while using Scout, the player won't be knocked out of Scout mode. Instead, they will be warned that they are receiving damage. The initial range of the plasmid is roughly doubled. Note: My version of the game would have Splicers spawn less frequently than in BioShock 2, although slightly more than in the original BioShock, so the player would get attacked less often.
Scout 2 Upgrade #1: Saboteur. Player can hack machinery while in Scout form. Unlocks Scout 3 upgrades #1 and #2.
Scout 2 Upgrade #2: Assassin. Player can use their melee weapon while in Scout form. Each hit drains a portion of the player's EVE. Unlocks Scout 3 upgrades #3 and #4.
Scout 3 Upgrade #1: Ghost. Player can move freely across the entire level while in Scout form.
Scout 3 Upgrade #2: Possession. Casting Scout on an enemy while in Scout form allows the user to temporarily control them for a cost in EVE which varies according to the enemy (Non-giant Splicers will have a smallish cost, while enemies such as Big Daddies and giant Splicers will have a huge cost in EVE). While possessing the enemy, they will have full access to their powers (for example, if the possessed enemy is a Spider Splicer, the player would be able to use its hooks as well as crawl on the walls and ceiling). If the controlled enemy gets killed or the player's time runs out, they will be ejected from Scout form and will return to their body. Note: Possessing a Big Daddy will cause the Little Sister it's protecting, if any, to run away.
Scout 3 Upgrade #3: Arsenal. Player will have access to all weapons while in Scout form, save for the Research Camera and the Hack Tool. Each shot does not consume ammunition, but will have a cost in EVE. Player can only use base ammo while in Scout form.
Scout 3 Upgrade #4: Sanctuary. Player's body is immune to ranged attacks while in Scout form.
Hope you like it. Also, I would be grateful if anyone could send me the Scout 2 icon (and, perhaps, make one for Scout 3).