LuaTeX _is_ very fast. What makes it slow is luaotfload and fontspec (with LaTeX). LuaJITTeX is improving much, but a lot needs to be done on the two mentioned packages.
Short answer: no. In theory, it would be possible to increase the speed, but that would include a rewrite of these two font packages. Fontloading is not necessarily slow in Lua(TeX), but the mentioned luaotfload for example deals with all kinds of complex scripts which is not necessary in most cases.
You mean compiling LuaTeX itself or using LuaTeX to compile? I don't know about LuaTeX, but I've just noticed that pdftex gets magnitudes faster when you install it (including all fonts, etc.) on an SSD. It's very I/O intensive.
I was amazed about the speed increase. (although it's kind of obvious in retrospect..)
I have to try this! Also it's useful to separate very long documents in different .tex files using `\include` and then use `\includeonly{file_im_writing}` to only compile the part you're working on.
Well I mean LuaTeX (in fact LuaLaTeX) is too slow to compile tex files. I'm using a Mac and it has SSD. a simple slides takes 5 seconds to compile, which is very slow compare to things like pdfLaTeX.
Are you using Beamer? What CTAN packages are you using? Those long render times could have quite a few reasons but fonts are one reason for sure.
If you want absolutely instantaneous (on the order of ~100ms for full generation of entire thesis with multiple passes for TOC/index/list of figures proper enumeration) output, RAMdisks with all of your content - that means install, fonts, graphic assets, packages, etc is only the way to go (without re-writing large chunks of LuaTeX). When I needed a quick render loop for final alterations, I had ~6gb of RAM on a dedicated partition in /opt/tex/ on FreeBSD setup just for that and it was nothing short of a pleasure.