I've touched on this point before(and this is not really aimed towards you) but when people cite X rapper to counter the idea that Ja didn't pioneer anything, they are either confused on what's actually being said or they're being dishonest.
No one is or has ever argued that Ja was the first to be melodic or blend singing and rhyming as a rapper(though i'd argue he was the first, or either one of the first, to popularize the male/female call and response type records). What people argue is that Ja(and Nelly too) were the main artists to incorporate and popularize a more vulnerable, relationship heavy, soft-female oriented take on the rap-R&B hybrid sound.
I'm sure I said this in a past post, but acts like Bone, Snoop, and Nate Dogg was giving us hood harmony type tracks, not your shower singing sort of records that Ja was known for. From that perspective, I'd argue Ja(and again, Nelly too) were touching on more defining elements of the R&B genre then what came before because of that. For example, was 50 using melodies and such before Ja got over...yeah, but was 50 making records like 21 questions before Ja got over.