Originally Posted by POTD:
“But then it was hardly ever just Troughton and Jamie. Other than introductory stories where the new female arrived, they always had Ben/Polly, Victoria or Zoe with them as well”
That is a valid point, but Jamie, for the longest time, was the primary companion while the seasonal female companions came and went (and, as such, there were times when it was just him and The Doctor in the Tardis). Nowadays, men are only begrudgingly allowed onto the Tardis and only if they are the love interest of the (always primary) female companion.
The Doctor has had the chance this century to pick up several male companions. He even turned one down cold when the potential companion asked to go with him (the fake tour guide and Earth history buff from the Christmas Special with the Titanic spaceship). He only takes on board males if the primary female companion insists on them coming along and then he ditches them as soon as he can (think Adam).
I am just saying that, if you wanted a nice change of pace with the companion, make the companion male and not the ever-so-amazing, really, really pretty, even-ever-more-amazing-and-special-than-the-last-one, 20 something female.
That is what has gotten really, really stale; with the exception of Donna, all of the rest of the 21st Century long-term primary companions are all variations on that theme.