On the subject of the PK3s:
I own these buds, as I, like you, had a need for portable 'phones where I could not feasibly use ones that heavily isolate. Sure, 90% of the time when I'm out and about the ER-4P are stuffed in my ear.
But when I'm jogging, I can't use them due to bone conduction; the thumps of my feet hitting pavement become as loud as thunderclaps.
I'm very far from a basshead; I love my ER-4P and my AD700s, neither of which are bassy cans, and I owned a pair of DT880s for several years before selling them off (stupidly). The PK3s are definitely bassier than what I prefer... when listening to them in a quiet room without any ambient noise.
Out on the streets, with cars and people talking and yelling, babies crying, dogs barking, et cetera... the extra bass is helpful. All that ambient sound would have made the earbuds sound tinny and weak without that extra bit of bass, in my opinion.