How many primary powers are "ok" to skip?

I'm talking mostly for melee types and ranged attacks. I understand having lots of powers for different situations, but I also don't see the need for spreading out my slots so thin. I usually try and go for DPA, not DPS, so i generally skip 2 or 3 powers for my primary. Is this normal or am I missing out too much?

It really depends on the build.
If you have enough recharge you only need 3 attacks for a solid single target attack chain. I usually try to get some decent aoe potential too but a lot of sets only have one aoe attack. In those situations, you would expect 3 single target, one aoe (sometimes two) and your Build Up power.

As an aside, DPA and DPS are pretty much the same thing. The only time they will be different is if you have gaps in your chain.

Really depends on the build, global recharge reduction, and activation time on the powers. To give a completely non-specific average I'd say about 3 Single target attacks and 2-3 AOE/Cone attacks, and then, of course, your nuke if you have one as well as any attacks that are more for mitigation than damage (parry, divine avalanche, most of the darkness melee pool, Air Superiority, etc.)

It really, really, *really* depends on your build though. I can't emphasis that enough.

ill also agree that it depends on your build and how you want to use the character, technically you could skip most ALL of your primary except for the one your forced to take at lvl 1 lol (there are poeple who do that too for extra challenge)

For most of my builds i go for 4-5. Generally 5 because I get kinetic combat and 1 mako's bite.

Not counting kheldians or Arachnos soldiers, the most I ever skipped was four with my fire^3 scrapper. I took three single-target attacks, one AoE, and Build Up. I can't imagine skipping more than that without missing something important.

As long as you still find the character fun to play, you can skip whichever powers as you like. More than the build, it depends on the player.

Varies wildly from build to build, and depending on build goals. If you want to solo AVs, AoE attacks are mostly superfluous except for set bonuses. If you want to farm, a robust single-target chain is probably not necessary.

Some Mastermind primaries can easily take only 5 out of 9 powers - 3 pets, 2 upgrades.

As others have said, it depends on the build.

Some sets, like Gravity or Force Fields, you often don't want to take all that many. Other sets, you end out taking everything.

You would have to mention a specific primary and secondary and also your goals with the build for people to say more.

I was thinking about a /willpower scrapper. I didn't say the primary because TWs are not out yet, so not sure what is useful and what can be left behind.

No-one can advise you on what is skippable in Titan Weapons...
None of us have any clue on what the set is going to look like.
Due to the nature of it's activation times getting faster and faster, I would suspect you would need a whole lot of attacks to keep a fluid attack chain when they are animating as fast as lightning (assuming the mechanic makes much of a difference at all).

When it comes to Titan Weapons, the wait and see approach is all we can do.