At lvl 15, you can weapon swap and have access to 5 more skill slots and 1 ultimate slot

The limitation of skill slots on your active bar forces you to choose a set of skills that will best fit your build choice. You can choose any skill that you have unlocked, though you can only use skills from the weapon trees if you have that type of weapon equipped. There will be different situations in which different sets of skills will work better, so even if you are not actively using one, you may still have it unlocked to use when you do something else. By the time you hit end game, you have enough skill points to have points in every skill and passive in your class skill trees, 2 weapons skill trees, some guild trees, and all crafting skill trees. You can set up different builds, with different skill load outs and gear for different situations. If you're on PC, addons like Dressing Room help to easily switch between load outs. Also, remember that by level 15, you get access to a second ability bar with your back bar weapon. So you really have 10 normal skills and 2 ultimates available to you at any time. On a Sorc, you can actually get a 3rd ability bar, because when you activate Overload, you can set different skill on your bars than you have when Overload is off. Just put skills on your bar while Overload is active to set them up.

So here are a couple setups that I use on my Sorc in various situations:

PvE Heavy Attack double pet build
1: Endless Fury, Inner Light, Volatile Familiar, Twilight Matriarch, Empowered Ward, Thunderous Rage
2: Liquid Lightning, Blockade of Storms, Volatile Familiar, Twilight Matriarch, Daedric Prey, Energy Overload
OL: Power Surge, Dark Conversion, Volatile Familiar, Twilight Matriarch, Empowered Ward

Remember that pets have to be slotted on all bars or they will unsummon when you switch to a different bar.

PvP meta build
1: Crystal Frags, Crushing Shock, Haunting Curse, Inner Light, Hardened Ward, Shooting Star
2: Hardened Ward, Harness Magicka, Healing Ward, Streak, Daedric Mines, Overload
OL: Power Surge, Boundless Storm, Dark Conversion, Defensive Rune, Harness Magicka

You could also build for more of a Tank or Healer, focus more on single target or aoe, or utility like crowd control with roots and stuns. It's up to you.

Babellon wrote: »

So what you're saying Is I'm over thinking it, and that once I'm leveled more in a chosen class 6 skills will work even though I have 20 more on a menu somewhere. a foot of rope with an inch of grip. Alright.

Not really. Remember that outside of combat you can swap skills at any time. I have different skills I use in different circumstances. Am I in a group? Am I by myself? Am I in PvP? If I'm in a group, what are the other people in the group using?

Of course, there are certain skills you won't use in a specific build, but I try to level up every class skill and the guild skills that will be useful to my character so I have the freedom and ability to adapt to different situations.

@Babellon
I played Lotro before ESO, and I actually thought having 30-some abilities to manage was very cumbersome. It also meant there really wasn't much build diversity, since everyone playing that class just had all of their class skills on their bars all the time. In ESO, there are only 3 class specific skill lines. Everything else is available to all players. So which class you play has a smaller impact, though it is still relevant. But by limiting the active skills, the player must carefully weigh their options. I may want to run a pet, but can I really afford losing an extra bar slot to keep the pet active? And this is where build diversity comes in. Different players will prioritize different skills based on what role they want to play, what skills they prefer, even what gear they are wearing. It's actually a very good system, and if you know what skills you're usually going to use, you can get those quickly along with the relevant passives and basically be all set with only about 30-40 skill points. The rest then just become extra to apply to crafting or less used stuff.