Stoker was inspired to write about Dracula/Vlad by a 15th C pamphlet entitled "the land beyond the forest" (Transylvania) which he came across during his european travels several years before Jack started killing. Much of the stories inspiration is quite apparent from the names used in it and owes more to his knowledge of classical literature and mythology combined with his personal experience of travels in Europe as the personal assistant of globe trotting actor Henry Irving than anything else. He based his central character therefore on a military leader known to have slaughtered thousands, not on an unknown nutter with a knife (and a passion for disected Uteri) known to have killed a handful.

I think the inspiration for the main character is quite clear from the name of the main character, maybe thats just me
Marduk, you're a whiz when it comes to ancient religion and culture, but you're way off the mark here. You've either accepted, without examination, the assertions of a misinformed "expert", or you've jumbled up the details in your memory and are asserting inaccurately-recalled information as factual.
The pamphlet you mention was written in 1888, not the "15th century", by Emily Gerard, a Scotswoman who had married an Austro-Hungarian cavalry officer and settled in the village of Hermannstadt, in Transylvania. 1888, of course, was also the year Jack the Ripper was active in Whitechapel.
Emily Gerard
Land Beyond the Forest
Stoker's notes begin in 1890. There is no other evidence of, or reference to, any research, or even thought, concerning the project until that year. Your claim that he began to consider the story "several years before" is unsubstantiated and fallacious.
[The New Annotated Dracula, Leslie S. Klinger, ed., Norton, 2008.]
To hammer the final nail home in your suppositions, the title character was at first called "Count Wampyr" and the setting of the story was in Styria (where LeFanu's "Carmilla" was also set). It is a matter of documentary evidence that the character and the novel were conceived, and writing begun,
before Stoker discovered the name "Dracula" in the book
Account of the Principalities of Wallachia and Moldavia with Political Observations Relative to Them, while he was doing research in the 1890s in Whitby.
And finally, the association of Stoker's Dracula with Vlad III is spurious, and there are many reasons to reject the notion that Stoker definitively and purposefully linked the two.
Summary of this argument here.
Stoker came across the name Dracula in his reading on Romanian history, and chose this to replace the name (Count Wampyr) that he had originally intended to use for his villain. However, some Dracula scholars, led by Elizabeth Miller, have questioned the depth of this connection. They argue that Stoker in fact knew little of the historic Vlad III except for the name "Dracula." There are sections in the novel where Dracula refers to his own background, and these speeches show that Stoker had some knowledge of Romanian history. Yet Stoker includes no details about Vlad III's reign and does not mention his use of impalement. Given Stoker's use of historical background to make his novel more horrific, it seems unlikely he would have failed to mention that his villain had impaled thousands of people. It seems that Stoker either did not know much about the historic Vlad III, or did not intend his character Dracula to be the same person as Vlad III.
Vlad III was an ethnic Vlach. In the novel, Dracula claims to be a Székely: "We Szekelys have a right to be proud..." And later "Again, when, after the battle of Mohacs, we threw off the Hungarian yoke, we of the Dracula blood were amongst their leaders." (Chapter 3, pp 27). The Battle of Mohacs took place in 1526, so if Dracula (or an ancestor) took part in it before becoming a vampire, he and Vlad III (born c. 1431) could not be the same.