I'm not supporting it, or condemning it, but high heat input welding does seem to be a common practice in the forging die repair industry.
http://www.mpdwelding.com/floodwelding.htmlook up "flood welding" on google and you can find a lot of information.
The bottom line is whether the welding technique provides a satisfactory product, and if it meets applicable codes. (not sure if there are any for die repair). In your case, if it causing slag inclusions, that could be a reason the practice is unsatisfactory. However, you can get welders entrapping plenty of slag with stringers as well if their technique is not correct.