No argument from me, but there is a mindset in the structural welding codes to lean toward prequalified groove details because most contractors try to work within the confines of the prerequisites of prequalification.
A WPS for an open root, welded from one side must be qualified by testing. Generally, the root would not be accessible for a direct visual examination. The engineer is responsible to address any specific shortcomings of the code that applies to "his project". I would say that in my opinion, this is one such situation. One shoe doesn't necessarily fit all. Depending on the nature of the loads, "excess root reinforcement" may be a non-issue, yet, under other loading conditions (think cyclic loads), the root condition may be a serious consideration.
I throw darts at all the codes, not just AWS, just to remind them they are not infallible. All in all, they do a pretty good job of addressing the conditions the vast majority of us are likely to encounter on most day to day work. The structural codes give the Engineer the authority to address any situation or condition that aren't addressed by a particular code. This is one of the situations where I would direct my concerns to the Engineer for his input and resolution. If the code doesn't address the issue, it is certainly not within the inspector's purview to make a final determination.
Best regards - Al
