1) The death of Davros. Not because of my feelings of anger and ick around the Davros-driven Genesis origin, but because I want to see what would happen after Davros. How would the Dalek culture evolve from that point on, without his megalomaniac thumb on the scale?*
2) Have creatures of the same (or similar) species as the "Monsters" in "Flatline" be the Goodies. After all, we never did learn the original beings' motives -- they may have been a rogue group of mad scientists, or criminals on the run (see also: the Slitheen). Part of the conflict would be can the Doctor overcome his prejudice against beings of an entire dimension?
3) The return of the Rill and their "chumblies," from Galaxy Four. Mainly because they are a truly alien alien (they breathe ammonia, instead of oxygen) an that would raise a logistical obstacle to overcome, if the Rill and Team TARDIS are to save the day together. You don't always have to make the big baddie bigger and badder to raise the stakes. Also, the Beeb has a special effects budget to do the Rill justice, now.
*( Spoilerific footnote to #1 )
2) Have creatures of the same (or similar) species as the "Monsters" in "Flatline" be the Goodies. After all, we never did learn the original beings' motives -- they may have been a rogue group of mad scientists, or criminals on the run (see also: the Slitheen). Part of the conflict would be can the Doctor overcome his prejudice against beings of an entire dimension?
3) The return of the Rill and their "chumblies," from Galaxy Four. Mainly because they are a truly alien alien (they breathe ammonia, instead of oxygen) an that would raise a logistical obstacle to overcome, if the Rill and Team TARDIS are to save the day together. You don't always have to make the big baddie bigger and badder to raise the stakes. Also, the Beeb has a special effects budget to do the Rill justice, now.
*( Spoilerific footnote to #1 )