Personally I wouldn't agree with the perception that you have stated. When a case goes to trial it is the strength of your barrister that assists in winning a case -- not any actions of a solicitor.
I'm in a similar situation and frankly I do not believe my solicitor is dealing well in my case. I use one of the big firms who are unduly burdened down with massive litigation cases, and my case may be so tiny that they cannot be bothered.
Changing Solicitor
What are the implications changing solicitors mid litigation. Does it give out a signal to the other side that all is not well with the case?
Wouldn't have though so. I have had to change solicitor in the past and didn't derail the case. Make sure that you get all your docs from him/her and settle up any funds due before you appoint a new one.
No it doesn't give that signal. Your problem will be that to move from one solicitor to another costs you more. Be very sure of your reasons for moving and more importantly your reasons for going to court. You're on here a while so I guess you've a very good idea of costs should you lose. Best of luck.