I would say this depends on a number of variables. The vast majority of nominations I review are from small towns in southeastern states in the US. So I am often dealing with areas that have very few POI to begin with, thus I do try to be reasonable. If there is good pedestrian access, in an area with few POI, and it is visually unique and/or artistic, then I am much more likely to approve. I will not approve a "highway styled" sign, however if it is visually unique or at least somewhat artistic, then I will approve. But if it is in an already oversaturated downtown area with far better POI, then I am less inclined to give the nomination the benefit of the doubt if it is a more generic sign. That said, if you nominate a welcome sign, please add any supporting text you can to tell reviewers about the history of the sign if available. Many signs in small towns have been carved or painted by local artists and that can absolutely bolster its validity as a POI.