i think within the next 5 years almost no chance of enbloc (off chance for you can never rule anything out)
As for capital appreciation. you never know, if the market recovers, it'll be too slow for you to react.
As for capital depreciation, there's always the chance you get stuck with this place, and the final en-bloc price is subpar.
Bottomline is you never know what the future brings. Yishun isn't that popular, but prices for northpoint is fairly high compared to other areas in the north for example, albeit its a MD.
On a rational side,
1. i don't think prices can go down much more, unless a major crisis strikes.
2. Prices will not shoot up like before either.
3. If you have calculated a finances and you definitely need a place to stay, otherwise you'll be bleeding through rent, just get what you like, it seems you have been conservative on your budget estimation which i think is wise.
4. This is Singapore as with any other cities. To have a roof over your head is better than no roof. Usually right after CM is the coolest market, sometimes right after CM is not a bad time to buy
5. There will always be more lucrative developments with more potential, but if you're budget tight you're budget tight. The alternative is to wait until you have more budget, but how long? And how will the market move? Sometimes patience reaps, other times, patience bleeds and you miss the boat. Unless this is your second property and you're banking on investment/en-bloc gains, treat it as a home and not an investment, then can just spend enough time in the market instead of timing the market.