This is an interesting question, and one that I looked into fairly recently.
A simplistic answer to your question would be that yes, more internal links will distribute link juice across your site much more evenly, like so: Home page (100%) -> 25 internal links (4% each). As opposed to something like: Home page (100%) -> 4 internal links (25% each).
However, to truly answer this question there is a bit more detail involved.
As with most things in web design, there is a trade-off. For example, take a concept like the mega-menu navigation you are currently using (i.e. a menu with loads of links in a drop down). There is an argument to say that mega-menu's are solid from a usability point of view, most particularly for e-commerce sites. This is because there is a vast amount of products to sift through, and getting to the one you want in as few clicks as possible is quite important.
The trade-off for using a mega-menu, in my opinion, is that it is quite poor in terms of link juice optimisation. This is because the Google algorithmn 'sees' the links from every single drop down as a live internal link - regardless of the hover effect.
In your 'funeral planning' drop down alone, there are 53 internal links that appear on every page. Essentially, every page on your website is linking to every other page, so the link juice is spread evenly. At a guess you have at least 300 internal links on the home page, which would translate to 0.33% of link juice per page.
- Please note this is a massive over simplification, because the algorithmn weights the links differently due to position. See #5 here on the following link (also bear in mind the date of the article!): http://moz.com/blog/10-illustrations-on-search-engines-valuation-of-links
- Also, a portion of link juice is 'lost' when passed, to prevent an infinite loop. An estimate is that a page only passes 85% around 85% of its total. Saying 100% means simpler maths to illustrate the point above
Now this is not to say that mega menus are a bad idea, it is just a trade-off in favour of Ux over internal link optimisation. In these situations you need to think what is best for your own specific situation.
Hope that helps
Oli