Generalisation? about what? the quality of SW expanded universe? The EU stories are overblown fanfics written by third rate hack authors,
Yes, GL does take some elements from the EU but as for major storylines they are subject to change at his whim.
While going with the clone thing for boba, he still ignored the other theories
i.e jaster mereel and a former stormtrooper. Ultimately it was just a small aside to please boba fett fanboys.
With aayla secura he saw a comic cover featuring her and decided he would "realise" the character - again utterly ineffectual and just there for eye candy and she is someoene to be killed off.
As for Coruscant - it could have been called Planet Monkeyfish and nobody would have cared.
Being well versed in EU lore does not imply that one's opinion concerning SW carries any more weight than other people, nor should one assume any superiority as a result of having read SW books. If anything it is more something about which one should be ashamed.