I do not agree with such calculations because it involves a lot more factors than pure mathematics and there is a fallacy in your argument but never mind. (i.e. by your logic, as long as there isn't any team or candidates who win seats other than LTK, then nobody could hold the ground in Hougang!)
WP's branding is the strongest among the opposition parties, amidst whatever shortcomings it has. You don't need to look anywhere else but just its sales of its publication, Hammer. But I do agree with you, branding could be destroyed if we are not careful. It is precisely so that WP takes a very conservative approach to protect its own branding.
There is no right or wrong in this, just a matter of perspective because nobody knows WHAT IFs and such.
There was an offline discussion about branding vs personality not so long ago. Some may think that personality is more important than party branding, even go to the extreme that says party branding is immaterial or doesn't really matter. The other end would say that party branding is MORE important than personalities...
I believe that the truth lies somewhere in the middle. Yes, the party's branding depends a lot on personalities or individuals in it but that doesn't mean that party's branding does not matter. If a party's branding is very bad, anyone who stood under its banner will suffer.
If you are talking about the ability of individuals to enhance the party's branding then it really takes time... it will take even longer time for one to enhance a party with very bad branding.
Goh Meng Seng
Take WP's vote in Hougang minus WP's average vote elsewhere and that premium is Low's premium. The difference is about 20%. If Low is not in Hougang, his successor gets 62% minus 20% = 42%.
Without Low, WP is very shaky in Hougang. And I'm saying very. Let's not kid ourselves. If WP's branding were so strong, they would have crossed 40% in every seat contested.
Brand name means nothing as it can be destroyed. SDP once had brand name and it won easily more seats and votes than WP which was an older party, for about 2 elections. You can lose the brand name by making the "wrong" moves like SDP or kept underground totally like WP. WP could have avoided the predicament if it didn't play too safe, but it might be too late now since you can't build up something in such a short time when there was 2006 to 2010 to do so.