I have 10 characters, and it already feels like with so many characters there is no attachment to any of them.
Personally I'd prefer just have 1 for each class but the ability to change the loadout on the fly between roles. Have 1 Templar, rather than 1 Stamplar, 1 Tankplar, 1 Magplar.
It would be nice if there was a function using the lore of ESO where we can merge characters of the same class. The end result being 1 character with 2 loadouts, the 2nd loadout changes the race, attributes, CP, skill loadout on the fly.
Lore - To do a soul merge, you need to select a Primary character (appearance, and any quests completed that required a choice get priority) then you take your character that is going to be sacrificed to Azura, where she gives that character his/her soul back, which results in their proper death. The primary character receives the sacrificed characters 'essence'.
Requirements - The Primary character has to complete Cadwell Silver to accept a sacrifice character and Cadwell Gold to accept a 2nd sacrifice character.
Result - Inventory of primary character is increased by 100, bank is increased by 20, they have the option of a second loadout and the option to change their racial passives to the sacrificed characters racials. Two different sets of CP. Two different sets of Attributes. All base skills are universal on all loadouts, but morphs can be different.
Cons - You will lose 80 potential inventory slots on your account. You will also lose a character slot (but not really, it has just been added to another character) but you will regain it if you delete the primary character.
18 potential total slots, 6 classes, you can either have 18 characters or 6 characters with 3 loadouts each. Nothing is forced on the player, it is simply for those that want a cleaner and more meaningful character list.