I know that young Ronaldo was a force of nature but his peak was very short compared to CR/Lewa. A good chunk of R9's legacy is dictated by his WC win. Lewandowski is handicapped in this regard as he plays for a comparatively weak nation and has almost no chance of winning an international tournament. If he had been Brazilian/Spanish or something and bagged himself a WC or Euro win, he would have been held in a much higher regard.
Lewandowski is closer to R9 stats-wise than he is to CR. According to transfermarkt, CR has 672 goals and 229 assists (901 goal contributions) in 893 games. Lewa has 459 goals and 128 assists (587 goal contributions) in 630 games. R9 has 295 goals and 77 assists (372 goal contributions) in 452 games.
Moreover, R9 only has 14 goals in 40 CL appearances. The format was different before 1999, but still. Lewa has 73 goals in 96 games. After the nostalgia starts working in Lewa's favor as well when he retires, especially if he manages to bag another CL or two, he will be rightly regarded as one of the best forwards of all time.