Once Again, I think it depends. If you get the page io latch error then it can only be one thing. depending on capacity and load everything eventually has a limit.
I worked in a place where we did not have a SAN guy for quite some time, when we got one on board he made a lot of changes and performance increased. But i wasn't a network or SAN guy, and was a newer DBA so the changes he made with regards to partitions, striping, and even out of date driver updates, network gear in between the DB and web servers, were all eye openers to me at the time. But are things that have stayed with me ever since.
I would say if the tempdb is appropriately sized, with 2-3 datafiles more you are probably okay. but you would want to make sure using the queries refrenced that the temp db is indeed your problem and it is not an IO problem. Do the investigation and the truth will out.