Personally, my feeling on alacrity on DPS toons is that a little bit isn't terrible. It is going to be a DPS hit (as tested on dummy and in sims) as it makes resource management harder and takes away from other stats that directly impact your DPS.

The benefit is it allows you to be more mobile. For classes with long cast times, you can be rooted for a long time and many boss mechanics will require frequent movement. Alacrity helps here, in these real world situations. For situations that do not require movement, it'll hurt your dps and your maximum potential dps.

B/c of this, I think it's decent for a newer player not familiar witih raiding and boss mechanics. You tend to run around alot in operations b/c you're not sure where to be and can be overly cautious. As you get more comfortable with boss mechanics you'll more efficient with your movement and don't loose as much to downtime while running...so alacrity isn't as useful.

Alacrity can be obtained via relics though if so desired. For a fresh 50, you can carry a power and alacrity one and choose which you want to use situationally. They're not BiS relics though, so you'll want to swap them out as you get better gear.

You have to be careful with alacrity because you'll heat up faster, and heal for less.

Its going to take more casts to heal the same amount, and the casts come faster. More casting + Faster casting = Lots of Heat

You should be fine as long as you stack surge to your preferred number and then splash in a little alacrity. But only add alacrity once your surge is "maxxed".