I do not know how Latest global edits is implemented, but it would be nice if it was browsable. If you do not cache all edits (I doubt it), you could get only latest ones from each wiki (like 50 or so), and on pressing next remember only the latest displayed edit for each wiki, and get the changes from that point. I hope my explanation is clear enough.
Topic on Talk:XTools
It goes quite slow, is the problem. For a more thorough review of individual edits across all wikis, I recommend trying the Global user contributions tool, which is optimized for this purpose. This is linked to at the top of the XTools Edit Counter.
The GUC tool is limited to 20 edits/wiki.
Probably for the same reason, that it goes really, really slow :/ I can see from the production logs that the XTools global contributions, as-is, often times out. That's why it's loaded via AJAX (after everything else has loaded), so as not to slow down the whole tool.
We might could allow this in the dedicated global edits page (e.g. https://xtools.wmflabs.org/ec-latestglobal/en.wikipedia.org/Mik), and if it times out, well, it times out :) I see that the tool loads quickly for your account, so it is certainly true that for many people this would work quite well.
I've created phab:T190956.
This feature has been deployed. Let us know if you have any issues.