Two questions about word2vec and gensim
Run the lower casing operation before running stop-word removal since it is case sensitive.
Your window size, currently set to 2 is probably too low. Run it with default setting of 5. It will allow more natural similar pairs to be discovered (words frequently found in similar context but with distance more than 2). It would be also helpful to increase the minimum count threshold to weed out low frequency words which can give rise to spurious correlation.

In general, word2vec needs some manual tuning before the results start subjectively making sense (unless your dataset is very large).