Imagine if you were able to transform (shapeshift) into another creature, undead, or daedra. This would be a great addition to TES. It would give fighters the opportunity to try a magical role like an imp, and for stealthy people to try something stronger or more arcane. This would bring more variety and techniques into the game instead of repeating the same boring moves or sword strikes for any class. This could be added simply into these two below options:

1. Add Shapeshifting to Alteration-

A conveniant opportunity for shapeshifting. With the many enchantments you can make on an enchanting altar, you basically wouldn't use any of those skills anyway. Even as a pure mage I never used their spells or trained up that skill until Mora's Soul Trap was added to my spell list tempoarily. Alteration magic alters you, a friend, or an enemy; essentially the same as shapeshifting.

2. Add Shapeshifting as a Power-

There are a few problems with my first option, such as the fact that you would have to be a magical prodigy to reach up to levels of moderately good creatures and that someone who just raises their alteration at level 1 could make the game very easy to complete. This is where the second option comes in. Having it as a greater power could make it work only once a day so the game doesn't get easy. You could also restrict it to certain levels (or maybe to people who have killed the creature my collecting their remains to learn the greater power from a tutor, eg. 6 daedroth teeth to learn shapeshift to daedroth, 25 bonemeal and 2 staves for lich shapeshift power etc.). And as a power, you can ensure that the player can reach a maximum of 1 to 3 powers. It would also prevent people from putting it as an enchantment or a spell.

Advantages of Shapeshifting:
- more variety and technique in gameplay
- possibility to play more styles of fighting
- opportunity to play as favourite creature
- reduce boredom and predictability
- more alteration spells (if first option chosen)
- more side quests (if last option chosen)

What Shapeshifting Does:
- Temporarily changes attributes and skills
- Temporarily changes spell list and active effects
- Temporarily changes inventory and encumbrance (quest items not affected)
- Temporarily changes the way you interact with people and enemies (eg. disguise yourself as ally to enemies or unable to interact with NPCs)

Please comment on your opinions of this option.

This was seen in morrowind, it MAY be possible in future titles, as it seems there's a very rampant wanting of such things. The only thing I'm surprised is that the khajiit in any form don't have like a weretiger mode. There's mods to cover shapeshifting, still trying to find one I like.

We have a suggestion thread open for TESV

Since anything won't be added to TESIV (unless you ask for a mod) I'm assuming you're making a suggestion for a new TES game

http://www.gamesas.com/bgsforums/index.php?showtopic=1068896

Yep, this might be better for discussion in the TESV suggestions thread.