In general a small number of requests is fine, but large numbers
(using the wikts as a live back-end database) is not so good. (Note
that "live mirrors", re-presenting WM data as part of another site are
explicitly prohibited. ;-)
What you should probably do is use the XML dumps from
which at the moment
(thanks to a bunch of work done after a lot of whining from us ;-) is
running on a 3-4 day cycle. It is very reasonable to download each
wiktionary's dump file as produced (not hard to automate). The English
wikt dump is running right now as I write this.
Then you can load each as it arrives into your local cache or server
as desired, and use as you will.
You can also get the en.wikt dumps from
updated mid-morning UTC every day.
These are a bit smaller, as they only include the content pages. (Eg.
you won't even find the Main page in the dump, as it is in Wiktionary: