So even if you achieve parity across platforms, Office users are going to find a lot to complain about... with reason. Not because Office is great, but just because Libreoffice is lacking in polish, still, in so many ways.
I've evangelized Libreoffice to users for years, but some parts of the suite are just terrible no matter how you look at it, and meanwhile alternatives like Google Docs and Gnumeric have established themselves... Even if you improve Libreoffice across the board, this isn't really going to drive adoption so much as lubricate it slightly for people who want to replace Office. Things like Steam encouraging game development for Linux are going to have a much larger impact.
(1) The responsiveness which I guess is from hardware acceleration. It's like comparing a $60 cheapo tablet and an ipad or Al Bundy's old Dodge to a 2014 Camry.
(2) The need to flout basic Excel conventions as if that's somehow lauditory. LibreOffice has made some strides here (hey you can use commas in formulas again) but it still feels like someone from Samsung should be put in charge of the whole thing.
2) I don't see the need to slavishly follow Excel conventions, but I don't know of any evidence that Samsung would be a good lead developer of any software. Be that as it may, Samsung is free as anybody else to contribute to the LibreOffice project.
I think 2) was a joke about Samsung copying Apple.
Basically, LO needs to be able to import the sort of monster power user spreadsheet that takes 16 hours to run in Excel, and run it fidelitously in 12. These guys sign the cheques.
What would that take?
1. Get a pile of example spreadsheets. (Code to real-world examples, like Wine does, rather than abstract specs that are often inaccurate.) This will be the hard part.
2. Every OOXML tag in the documents needs to be correctly imported and understood.
3. The VBA in the documents needs to run perfectly.
4. Optimise the hell out of it.
That gets LO good enough to seriously compete. Then you make the IDE as good for those users as Excel's is.
LibreOffice people are working on speed of execution in Calc