The 'view spec' thing is idiocy in its purest form. Consider the following case:
-You create a branch and a view that shows files in the branch on top of the trunk.
-You edit file A.
-Some other guy edits files A and B so that B won't work without the changes in A.
-Your branched version blocks the other guy's changes in A so you have broken source code until you merge.
The same thing happens even if you are both on same branch. In that case, the explicitly checked out file blocks any changes to tip or tagged revision.
Now think what this becomes when there are lots of files and several branches / tags in the mix. Yes, ClearCase tracks every single file separately and does not have any atomic operations, which makes things very interesting.
With dynamic views, you see everyone else's changes immediately, which opens opportunities to all kinds of messes. Heck, if your software takes a while to compile, the source code can change a few times during the compile (remember, no atomic operations, so changes happen one file at a time). The dynamic view also needs constant access to server. The latest and greatest version I had to use just froze when the connection lost and crashed completely if the machine came back to net with different IP address.