What do you find complex about iPhoto?
iPhoto is a $15 app. Lightroom is a $150 one, though I have to say, I would not consider it a "simple Photo cataloging software". It has a much more steep learning curve than iPhoto. No, there is no way to sync LR with your iPhone. You would need to export versions from LR to folders in the Finder, and sync those.
Aperture has an upgrade path from iPhoto, is half the price of LR and can sync with your iPhone. But it too has a steep learning curve and again I would not call it a "simple Photo cataloging software."
What iPhoto, Aperture and LR have in common is that they are designed for losslessly processing the images from your camera - a digital darkroom as it were - as well as cataloging and managing your photos. Photoshop is an image editor. It's overkill for about 95% of photographers, though excellent if you're a graphic designer or laying out magazines - Photshop Elements is more attuned to the photographer's requirements (and a lot less expensive). However, if you work with Aperture or LR you you'll rarely use Photoshop at all.
You can sync any folder of photos with your iPhone.
Regards
TD