Up to 2004 the company primarily made the Hunter Original Wellington in darker colors, attracting the upcountry richer folks who use the boots for functionality. That started to change when the target audience shifted to younger generations and more models and colors were introduced. Not much later the Hunter Original Wellington boots were available in colors like bright red, pink, purple, and with colorful patterns (picture below from Peter on Flickr).

The obvious problem a company mainly selling one product line is that it is hard to attract new customers, and when you have one, they tend to buy only one pair of rain boots. A new buyer is much more likely to buy other fashion items to combine that one pair of rain boots to make a new look instead of buying several pairs of rain boots, especially given the price range of Hunter boots. Collaborations with other brands, like Jimmy Choo, to make limited edition boots only spur sales in the short-run with little impact on the overall results. Jimmy Choo Hunter boots; photo from stylefritzz.com

To increase market share and profits further Hunter started to focus more on other products, some related to the Original Wellingtons while other products miss any connection to the heritage and production experience of the company. Inside the Toronto Hunter brand shop (picture from blogto.com) with high boots, low boots, umbrellas, bags, and coats:

While I do understand the reason for offering more products, I see a major problem with the lack of focus on the range of products. The company can transfer itself from a rubber boot producer to, for example, a rainwear fashion house, but some of the items offered miss every connection with the original products of the company. Take for example the adjustable slides; made without rubber and completely out of place in rainy weather (photo from hunter.com):

The connection between a rubber rain boot and a rubberized rain coat is easy to make, but I do not see how scarves, bags, and knitwear come in to the picture. It comes across as the company is trying to milk its brand name as much as possible, and it is forgetting to stick to its heritage and the production knowledge it has built up over the years.
While the move to other products surely pays out financially, it is not part of the overall image I would choose. I simply do not associate Hunter with bags, knit-wear, and flip flops, making these products overpriced unfashionable items in my view. Better, more fashionable, and similar items are available from other brands at much lower prices.
Items like the ponchos or raincoats would seem in-line with the company, turning these products into things to consider after buying a pair of rain boots if you want to combine several Hunter branded items into one outfit.