Not making a fully featured character builder on the basis that some groups use houserules, when there is absolutely a baselined ruleset, is not a great argument. Especially when the product is so expensive.
neither of these statements are particularly good arguments. it is a virtual table top its not a character builder. character builders are another beast altogether. FG does not advertise itself as a character builder. roll20, d20pro, maptools are also VTT products - not character builders. Hero Lab is a Character Builder and costs $30 by itself. For a single ruleset.
The product is not expensive. $4-10 a month or Fantasy Grounds or one off purchases of $40-150 are likewise good value. They compare well to Roll20's pricing. Feature for Feature the product represents excellent value. The D&D 5e content is at list price or lower for the same product in physical form and this product has gone thru so much more conversion and enhancement to make it work well in a VTT environment.
The automation and enhancement you get in FG is so far above that in any other VTT product. You dont need to buy any 5e content to use the amazing combat and spell mechanics. You can enter data in by hand as you go or spend time prepping in advance.
Your dislike for the UI doesnt make you other comments true.