Citrix Farm Design and recommendation

I have got a new customer where they have two citrix farm with two different versions.
I have attached teh screenshot of the design doc.

Customer also raised few queries like this

Users often can launch an application from WI but after a period of time sometimes they receive an error when trying to launch another application.

 Installing Citrix on new London Servers sometimes fails.

If stopped sometimes IMA Service will not start on a London server

Link between London and Singapore can sometimes get flooded with traffic

Printing some time very slow


They are asking for any changes need to made in Farm and any recommendation.

Can anyone help me on this.. I am also seeting all the details But any recommendation would great.


Note:- I am not understanding one part that "Round Robin with WI".
I know round robin iis use for what reason... But could any one help me on this area also appreciated.

Thanks
design-doc.doc