If it's a presentation for a life-saving treatment, the time lag is acceptable. If it's a site to make animated GIFs with a funny extension (SWF), it's a bandwidth hog.
What flashers always miss -- people who get broadband are
more impatient not less. 20 or 30 seconds download time on dialup is noticeable. 20 seconds on broadband means your site is broken.
Ideally, you would not have a graphic designer (or designers) review this. You'd put the site through a properly conducted user test. Reviews are largely from non-users, who will not become users.
When you actually try to use Wix, other problems occur. Labels overlap, hampering readability for users. "Create a Stunning Website" gets covered by "oh yeah, Wix websites are search engine friendly"
And nothing on the site compelled me to create an account. Seeing I have Texty and Cushy CMS accounts, this would seem to indicate future problems.
You should have some users actually go through, get memberships, create a site or two,
and watch them. Don't ask what they think, see what they do. Consult with an interaction designer who can evaluate an interface, not an interface decorator with personal preferences.
Related:
First Rule of Usability? Don't Listen to Users