Years ago I did the intercessions fairly frequently in my home church. Now as an assistant priest in a different parish we have a rota....so the only time I'm called on to do it is when someone is missing.
The main problem for me is the length of time taken by some people. One man here goes on for 20 minutes which is ten minutes longer than my sermon!. I try to get myself comfortable at the beginning!
It really shouldn't be necessary to cover everything at great length I think and the long lists of the sick can get boring which is not the aim of the prayers at all..
The main reason to intercede on behalf of people or global situations every week is to direct the congregation into the much needed prayers that come from the heart. If the congregation has switched off mentally they are not going to do much praying!
Intercessions shouldn't be intended to impress..they should be direct appeals to people for prayers.
I have in the past used various books to help with this but I know in my heart that I touch people best when the prayers are not prepared and given with sincerity and love.
As on Twitter, brevity is definitely a virtue!