I would think you would do a lot better.

One person concentrating entirely on the healing/cleansing, and able to pillar-hump, is a significant advantage.

Similarly, you focus purely on the damage and killing, which cooldowns to click and when.
Plus it will be easier to be 20-30 yards away from your healer most of the time, which means you can Death Grip to protect them even more so than playing solo.

If you're running with a healer of your own, that will cause them to lag back a bit.
If you're not running with your own healer, you're dependent on someone else to follow your team around both in BG's and Arena.

You could likely do most dungeons, via a Blood dual-spec and a pug healer.