After reading a load of crap, I'll now give MY opinion!
I think it's time the Doctor had TWO companions. And preferably for a long while, not just the odd episode or two.
Look at the companionship that DW2 had with Jamie and Zoe!). It makes it more of a family. David Tennant had it with Rose and mickey (albeit brief!). It makes it more interesting to see how they all inter-act when they are split up or whatever!
OK - it got a bit much with Dr 5's THREE companions at times, but it was still acceptable, whether they wrote one out or the other for any particular story.
The NEW Doctor has always had more than one companion anyway (as mentioned earlier): Adam, Mickey, Jack, .....dare I say the beloved Jackie Tyler!! Gosh I loved her!!
Get Jackie back on board I say!