It can be too large, depending what you want it to do.
The late W4RNL has a good article on multi-band use of large loop antennas here:http://www.cebik.com/content/a10/wire/horloop.html
I've put up and used a number of loop antennas. Some have worked well, some
haven't. I've had better results on 40m and 80m than on the higher bands, and some
of that might be due to antenna height.
For NVIS work, a horizontal loop is great on the fundamental, but has a null overhead
on even harmonics. Fortunately the null is fairly narrow, perhaps +/- 15 degrees, so
it can still cover moderate distances.
The pattern develops more lobes and nulls on the higher band, as shown in the plots
in W4RNL's article. For the last couple of years I've put up a full wave 80m loop for
Field Day, carefully arranged so the major lobes run North, East and South (which is
optimum for Oregon.) After plotting the radiation pattern on a map, I discovered that
the lobes were a bit narrow on 20m, and considerably so on 15m and 10m. I could hear
and work strong signals on 15m, but there weren't a lot of them, and only in specific
directions. This year I was on crutches and couldn't put up the big loop, so settled
for a 40m doublet fed with twinlead and did about as well operating 40, 20 and 15m.
It would be interesting to compare maps of the results: the loop worked well overall
and made lots of contacts (more than the other stations combined) but had to be
aligned fairly carefully to keep from aiming the null right at the major concentrations
So large loops can work in many directions on the higher bands, but will also have
a corresponding number of nulls. It's not a bad overall antenna when you aren't
particularly concerned with the direction you are working, or where you can align
it for those areas of particular interest to you. You may find that you want to have
a second antenna to help fill in the nulls.