So sorry, D, that this fellow ruffled your feathers. I'm giving your client the benefit of the doubt that this was an innocent request for a second opinion, and not a staged show to attempt a killer price negotiation (although, there's no harm in trying, right?)
When mulling this all over, I hope the client takes into account the total unprofessional behavior of the other jeweler, err, "appraiser." To totally assault another professional's merchandise in such a crude manner, within eye- and earshot of both client and professional offering the diamond, speaks more to the "appraiser's" character than it does the diamond.
And yes, if one were seeking out an INVESTMENT stone, and one were to have no problem with the expense, a 2-plus carat D or Fancy Vivid would be an excellent way to go. It doesn't take a gnarly mouthed "appraiser" to know that, does it? However, even so, the difference in size, visual impact, desirability, and value between a 2ct and a 5ct diamond (most likely, regardless of difference in Fancy color range) IS significant.
And, just to play Devils Advocate, I must say, I was not aware that a colored or Fancy diamond that is not VIVID, or that any high-color diamond that is not D, is a piece of "doo doo." Someone should have told Elizabeth Taylor... the VC&A 7.25ct and 7.74ct LIGHT BROWN pear-shaped diamond ear pendants and 29ct LIGHT BROWN pear-shaped diamond ring given to her by Richard Burton were all pieces of you-know-what. Heck, they're not even YELLOW.
If someone wants to better understand the value of a large Fancy diamond, I'd advise him/her to check out auction results. For example, last year in Geneva, Sotheby's sold quite a few beautiful Fancy INTENSE yellow diamond pieces, as well as the coveted VIVIDs, of course. However, low and behold, there were some plain-old Fancy yellows that sold as well. Even the frumpy
Fancy yellows were good enough to be included in a Magnificent Jewels auction...
BTW, The Kimberly Diamond is JUST Fancy Yellow as well... (of course, it is also 55.08cts).
My advice: if you seek to make a significant investment in a diamond (and significance is all relative to one's individual budget, btw), be diligent. Do your homework. Know what you like. Recognize quality when you see it, both in terms of the stone AND the build of the jewelry piece. Know what similar pieces are, or recently have been, on the market. Have a sense of where the diamond market is in terms of pricing. And, when push comes to shove, know where your preference boundaries are. YOURS, not someone else's. If you can't have EXACTLY what you want, yet, still, you want to go ahead with a purchase, what elements of the piece or stone are you willing to give-up? What are deal-breakers?
And, when seeking a second opinion, find a reputable, UNBIASED professional who has nothing to gain or loose by advising you.