That's fine - if you only ever go above 35MHz.
I'd say it complements the AD9850 / 9851, rather than replaces it: put them together for increased spectrum coverage.
Personally, for a Network Analyser, I want coverage below 450kHz. That allows me to "tune" the IF stage of a conventional AM radio.
Others, working with LF and VLF equipment, may want even lower.