Yeah, I think England and South Africa are still unknown entities to a degree, everyone seems to consider them huge contenders which they might be but I wouldn't be surprised if any of the other three "top 5" teams picked them off without shooting the lights out. I definitely wouldn't say the same for NZ or Wales*.
South Africa are clearly a good side but beyond that bonkers game In Wellington I just don't see the hype so much, the draw this year was ok but it felt more like a sparring session, the first game of the cup made them look very containable and they will probably have to get through a Welsh side who'll happily do that for 80mins.
And on topic in this thread England are just mental, their supercharged and passionate performance against Ireland who were looking for three on the hop against them (which I think is very significant at this level) was devastating but I haven't seen it since and don't know if they can do it two weeks in a row. Wales wasn't as bad as it was made out to be but showed how containable they are, while Scotland just epitomised why I can't see them beating the teams they need to to win the world cup, especially New Zealand. I think the pool stages has been ideal for them, the rest and facing an Aussie side who I fancy to beat themselves before a ball is kicked swings things in their favour but going back to back against NZ and Wales requires something we haven't seen for at least three years, I'd definitely want SA if it came to it as an England fan. Not saying it can't happen but for me the contenders are NZ, then a massive gap, then Wales followed by England and SA with Ireland bringing up the rear.
*NZ not included, after that I think Wales are most likely to lose to a mental French performance and in the unlikely event of a Wales v Ireland final I'd nearly bet my balls on Wales.