If Sweden shall keep Finland and Estonia not even deleting Denmark and Norway from the map will help unless we do somethimg serious about Russia.
Apart from various ASB suggestions about deleting Russia from the map I would propose Peter being not so great and/or Russia falling back into long beards, vodka and internal feuds in the Imperial family after Peter. If we so postpone the time from which Russia is a serious threat to her neighbours for at least 5, but preferably 10 decades, I think the time for annexing territory without extraordinary reasons has passed.
The extraordinary reason could however be the Finns and Estonians not wanting to be part af Sweden or anything Swedish. They could end up like the Slesvig-Holstener, who got Prussian support for getting out of the rule of the King of Denmark, but ended up annexed into Prussia and finally parted - which was what they originally tried to avoid (the King of D. annexed Slesvig into the Kingdom, but left Holstein a Duchy ruled by the King of Denmark).
If the Finns and Estonians shall stay happy with Sweden it probably requires a quite egalitarian union, federation or whatever name it takes. The Norwegians had a relatively loose union from 1814-1905, but that wasn't enough to keep them, and is it realistic that the Swedes, being used to Finland and Estnia as remote provinces (and not an old Kongdom like Norway), will grant these nations equal status?
We will need some more PoDs - ideas?
Regards
Steffen Redbeard