For the CNT, the team edition of WTTC is easier than its individual counterpart because the lineup could be changed to avoid certain match-ups. At WTTC 2012, LGL avoided ML vs Boll (2-0 -> 2-3 at WTTC 2010) and instead went with ZJK, who ultimately won 3-2. ML has always had
a hard time playing Boll.
And if ML from WTTC 2017 is equal to the other two, then ZJK from WTTC 2013 should be equal as well, if not greater. ZJK was in poor form leading up to the event but everyone still avoided him in the warm-up tournament at home and ML was the clear favorite. By the same reasoning, WLQ from WTTC 2005 (untouchable) and WTTC 2007 (fended off RSM in SF and was down 1-3 in games, 1:7 in G5 vs MLin in F) should be equal as well.
You have a point, I tried to answer strictly from a "mathematical elo" point of view
In chess tournaments some players have exquisite performances here and there, for example a player who is normaly rated 2100 can have a performance of 2500-2600. It seems abnormal but it isnt. Same thing goes for table tennis
If we approach it from an "overall athletic peformance" combined with difficulty from several opponents on the way then my ranking would be as follows
1. zhang jike 2011 wttc, knocked out Joo sae hyuk, wang liqin, timo boll and wang hao, who was still at his prime, at his first attempt nonetheless
2. ma long 2017 wttc, chuang chich yuan, timo boll xu xin and FZD in the final
3. WLQ 2007, (2005 just seemed too easy lol) hou yingchao (he was a top defender back then), hao shuai, and finnaly beating an onfire RSM and eventually beating ma lin with a clutch performance
Decided not to include waldner's 1997 performance because it was a different game back then. Also I agree with you about world team championships, if you are a member of china it is easier to perform when you know that you have another two top players behind you to clean up the mess if you lose your match.
The only "nightmare" scenario for a chinese player in a team match would be to lose 2-0 or 2-1 & 2-2 and you are called to save the day, this unlikely scenario is the only one which can exceed a wttc singles final match in terms of difficulty