I think Sanga is marginally better than Dravid overall but he doesn't really have a better overseas record especially when you consider how little he even played outside Asia.
Away records for comparison.
Dravid 94 matches, 7690 runs @ 53.03
40+ in Australia, Bangladesh, England, NZ, Pakistan, WI, Zimbabwe, 29 in SA 33 in SL
Sangakkara 59 matches 5570 runs @ 54.07
40+ in Australia, Bangladesh, England, NZ, Pakistan, UAE, Zimbabwe, 36 in India 35 in SA 34 in WI
No not superior you’re right. Definitely on a comparable level though, and with Sanga having a far better home record as well as being more likely to actually convert and score a ton I’d still take him.
Interesting that both struggled in each others countries.