No. Aeroplan is still the best program in star alliance. What you mentioned are different airline alliances like oneworld, skyteam etc.

If you want to collect aeroplan, you will need to find flights operated by star alliance.
https://en.wikipedia.org/wiki/Airline_alliance

If you flight economy only, don't be royal to any airlines or programs. Just pick the cheapest and best available flight. Basically I collect all 3 programs which are AAdvantage, skymiles and aeroplan. So that I can collect points for almost all my flights.

But if you travel a lot (like every week or 2 weeks). Then you will need to find a best airline program to suit you and try to fly that airline all the time.

Also I wouldn't recommend to pick airlines in destinations. You should always pick the largest at your home hub. In your case, that's Cathay Pacific. The reason is the fastest way to get points is to sign up CC. But you can also collect points by staying at hotels, car rental etc.