Sounds like you want the same bike everybody wants.
All bikes are a compromise I would say the Strom is a great value compromise and as you can see by this forum so do many others.
The amount of after market gear you can get also tells the story of just how popular these bikes are, you can build the bike you want for not much cash.
The 1000 is definitely more bang for you buck but I found the 650 more fun to ride I just had to be on the gas earlier and brake later than my mates, if I did not spend so much time with a pillion passenger I would be happy with either in my shed, with a load on the 1000 makes overtaking manoeuvres that much quicker and safer.
If you are fit and healthy the Strom can go a lot of places it was not designed to go but they are heavy, so up hills and down hills becomes a challenge against gravity.
Off road the ground clearance is another limiting factor but on road it has great clearance so cornering is a blast.
If you found the SV650 slow you may want to test ride the 1000.
I was surprised by how quick I grew to love my first strom, it is not the type of bike I ever expected to own but has become my favourite ride.
Some of the 19 rides in my shed
2014 V2, Snoopy
2009 Wee, Pumbaa the pig
WR450F, The Blue Postie Bike
YZ250N smoker with rego, Stinky.
Yamaha MT09 (FZ09), The Scud missile.
Club Lead not Club Med.
He with the most toys wins.
Out of my depth in a puddle.
Live life on the edge you will see more that way.
Ridding a motorcycle keeps things in balance.
At the end of each trail and at the end of each day history is made.