Bill Gunston's "Jet Bombers" section on the Viggen said:-
" Extreme Mach numbers were relatively unimportant. The decision was taken to follow the formula adopted by the Type 35 (Draken) and use two lateral inlets of simple fixed-geometry form, but to make them appreciably larger and withe major axis vertical, standing well away from the fuselage with a gap for boundary layer air".
The Draken also had fixed inlets and in the "D" model these were extended forward until they were right next to the cockpit.
Possibly the long in (and quite large inlets) positioned well forward negated the need for fancy inlets - presumably there were some drawbacks but overall the balance worked very well.