As far as Sweden is concerned, it is possible to live in complete peace if you manage to become independent of Denmark while Sweden remains a subject. (Denmark will love you due to the "historical friends" modifier, and Sweden can't do anything as long as they are not independent). But that scenario also means that you'd have to take on both of them alone in your independence war. It also means that you'd have to take the province of Dalaskogen from Sweden in the peace deal (it produces a lot of copper) because else your economy will be too bad to sustain any kind of colonizing.
.
I managed it to use Sweden as shield against Muscovy, they peaced out and stayed subject, my Norway became independent and could join HRE via Schleswig.

(Didn't continue that run yet.)
Economic and innovative absolutely dumpster it in military policies. Expansion is a never-pick basically and definitely needs a look.
Those colonies are mainly giving you money too, and they are less efficient at it than economic or innovative (especially with +5 advisers), themselves outclassed groups in SP.
The only time I've touched it in the past several years was as a 50 point western tech custom nation in the new world, because the AI was colonizing too slowly and I wanted the achievement for owning all new world provinces. Outside that edge case, it's been a weaker pick than alternatives consistently. I've taken espionage more often in WC runs, though admittedly 7th for diplomat.
I realized I don't need massive military buffs, as long as I have good generals. I skip most of the often recommended military idea groups (never take defensive, started skipping quality, too) and I don't see the point for MIL policies, at least not if they buff the military quality.
And colonies give control over provinces with access to new expansion options, give many extra merchants and access to a lot of trading in "trade good" modifier. The earlier you reach this, the better.
But maybe I am also biased by the kind of runs I did lately, including African Power, Japan, Scotland and The Navigator.