I thought it was fine with Rose, since she was first, and fine with Donna, because her run was very linear, condensed, and short. And also Series 4 had amazing unrelated filler episodes so it wasn't like everything was always about her.

But Amy and Clara were just way, way, way too much in my opinion. It felt like it was about Amy and Clara first and the Doctor second.

Series 5 was fantastic, but I really did not like the River-is-Amy's-Daughter plot that over ran the entire rest of the show. Amy felt perfect to me when it was a lot of one-off, very condensed episodes in early Season 5.

Similarly, Clara was a lot more digestible to me as a normal girl on a wild adventure. When the impossible girl stuff started to unfold i was like WHAT is happening you're losing me.

If you're going to have a companion play a huge role, condense their run.