As someone who has watched a fair deal of science fiction and fantasy television not to mention, well, television in general...

It can happen, but it is very rare, that a show "rights its course" after seemingly losing it. One example which I am looking forward to is Nashville coming back for a fifth season after getting cancelled by ABC and picked up by CMT.

With Guggenheim in charge, things will never improve, and in fact they are likely to just keep getting worse.

What is normally required to get a fresh start and save a show from utter mediocrity is a change of direction and this change of direction can only come from firing the creative team. As long as you give the same creative team which was responsible for driving the show into the ground an "Okay" to make one more season, they'll feel entitled to keep turning out drivel to the audience.

It also has to do with having a strong core concept. A weak core concept which is easily eroded by bad writing may not be possible to salvage without stretching the audience's suspension of disbelief beyond the breaking point.

This is what has now happened to Nashville. It was a show with a solid core concept which the creative team mercilessly drove into the mud over three years until the trash was cancelled. CMT picked it up because of the concept and the showrunners got fired along with practically the entire writing staff.

That's what needs to happen here, in one way or the other. It's a show with a strong concept (the Green Arrow franchise) which also due to its comic book nature makes the viewers more likely to give the writers the benefit of the doubt.

It can be saved but it can't happen under Guggenheim and as long as Arrow continues to churn out good ratings by CW standards expect the quality to stay the same or keep dropping.