If you want general trends, look at the turnout. If they are less than 2014 or equal to it, there isn't much anti incumbency. That, however, isn't s guarantee that the BJP will romp home.This election in UP so far is based on single point agenda, single issue - Modi.
Either you are voting for Modi or against Modi. Issues doesn't matter, if you support him you will find reasons to justify your vote, if you are against Modi you will find reasons to justify that, doesn't matter if those issues ever affected you or anyone or if you can even spell those heavy issues.
Amazing election, and as expected if you are wearing a cap or long beard and even a direct beneficiary and candidate you are voting made your life hell you are still going to vote against Modi.
Similarly if you are from upper caste younger voter you are going to vote Modi even when your preliminary exam result for recruitment is pending from 1.5 yr and whole Modi cabinet gives a damn, busy in designing Merchandise to collect funds and creating ads.
Issues be dammed, reasons be dammed, it is all reduced to single point - Modi. Thanks to excessive pandering to hard-line hindutva Muslims are first time after long getting consolidated and not splitting vote, BJP is going to pay for it, how much we will come to know soon, a lot of this damage was avoidable and there was an opening when Rahul became Janeudhari and shunned Muslim symbols altogether. Later after establishing himself as "hindu" with soft hindutva credentials he is back again with Muslim appeasement thereby getting support of Muslims and allaying fears of congress hindu supporters.
BJP on the other hand instead of utilizing this opening, blunting the consolidation went hyper hindu! Even after providing 10% reservation to Muslim nationwide under EWS, limiting violence and riots to standalone incidents they still were able present themselves as extreme Muslim hatred just by promoting motor mouth fools.
There was lot BJP could have done to reduce this election from being for and against Modi to Modi + development vs others but nothing was done. Only good thing for them is first time voter are voting for them and it's huge block, strangely that same voter was ignored, mocked and even insulted at times by BJP.
On a different note, the Muslim population in Western UP is around 30 -35%. You can expect it to consolidate behind the SP+BSP. Where's the guarantee, however, that the SP+BSP's core constituents will support the combination? The SC's don't see eye to eye with the Yadavs and vice versa. Then there is the Congress & rebels of the combine to further complicate matters. This isn't a cut & dried affair by any yardstick. I think most of them victory margins in Western UP will be close except the RLD candidates.