@VITSUSADec 29.2018 — #If you keep same URL structure in WordPress, then there will not be as negative impact, but some fluctuation in the keyword may be happen. Because other factor also important for keyword ranking.
if you want to simplyfy all URL's then you can use htaccess to rewrite incoming URL to map to existing URL.
So you could have an ugly URL like http://my.domain.tld/forums/?id=hotels&place=uk&type=selfcatering&location=newport and you want to display a URL that is useful and memorable, well, you could just write out a URL of http://uk.domain.tld/newport/hotels/selfcatering and the htaccess rewrite rule used will map to the old URL.
This means that you do not need to go writing lots of code changes out... You can deal with most URL issues as long as you have a rule and a final catch all for any failed rules.