Just how experimentation-friendly is the skill system in The Secret World?
Solution 1:
No, you cannot 'Respec'.
Spent points stay spent. However, this matters less than your equipped abilities, which (once learned), can be changed at any time.
New Skills and Abilities are Cheap.
Getting to a basic level of proficiency at which you can comfortably adventure with a new weapon takes a fairly minimal investment. You don't need to max things out to be able to comfortably use that shiny new Blade you just decided to switch to, and you can always go back and repeat some easier quests (All quests can be repeated periodically) if you need some easy and quick XP. Which brings me to...
Skill and Ability points are plentiful.
Seriously, you will be swimming in points early on. More than enough to get a feel for everything that's going on, and easily enough to 'fix' any early bad decisions you might make. And besides, by the end of the game...
Yes, you can get enough skill points to max out everything.
Character growth in The Secret World has been pitched as 'Horizontal, not Vertical'. Which is to say that, if you focus on only two weapons, you can max yourself out rather quickly, yes, but there are enough skill points in the game to eventually max out every Skill and every Ability. After a point, character growth stops being about becoming more powerful, and instead becomes about having more choices. And the best part is that that point is wherever you want it to be. If you're not having fun with a given weapon anymore, you can change it. Anytime you want. You might need to duck back to some easier content for a little while, but that isn't a big deal anyway.
Solution 2:
It is not possible to respec in the traditional sense of "stick all your points back in the pool and then reallocate them". However, it's incredibly easy to gain points, especially as you progress through the content, and the lower tier abilities are very, very cheap. It should be largely impossible to get yourself stuck in an awkward spot for any significant length of time (and keep in mind you should always be using two weapons at once).
There are absolutely no caps on skill or ability gain.
The only other limitation that comes to mind is that you're limited to one Elite ability equipped at a time in each category (active and passive). Beyond that, there are absolutely no limits whatsoever.
I might also add that this game ENCOURAGES you to branch out horizontally - there are very many situations where you'll need to alter your build to handle content adequately. It's balanced such that it's easy to branch out your skills, so changing mid-stream should be no problem.