232 EF Typhoons were required to see the type through to its planned OSD with seven frontline squadrons and the required training unit and attrition spares. It's replacing the Tornado F3 (4 squadrons) and Jaguar (3 squadrons). That includes Tranche 3.
Using Tranche 3 as a FOA (GR4 replacement) would either necessitate a further reduction in AD/OS strength, or an increased EF buy.
Re JSF. It's a great 'first day of the war' F-117 replacement. It makes sense to the USAF as the 'Low' element in a high/low mix with the F-22. It makes sense to the USAF who have the 'infrastructure' of offboard kit (F-22s, E-3s, JSTARS, Rivet Joint, etc.) to make it work. It makes sense to the USAF who will replace F-16s (which often carry a relatively small A-G payload). What it is not is an F-15E/Tornado/F-111 replacement. What it is not is an autnomous air superiority aircraft. What it is is cheap (though becoming progressively less so) and industrially vital for the USA.
In many respects EF Typhoon is a better aircraft than JSF for many air forces. A better air to air superiority aircraft (as long as everything works) with long sensor range, a great MMI (especially with DVI), good supersonic acceleration, low frontal RCS and shedloads of long-reach BVR-AAMs. Some of the planned EF derivatives, with conformal tanks and all the gear, might well be quite good long range interdictors, too.
The Gripen is also a great choice for many requirements too, and would perhaps be a better fit for the RAF, if we were not relying on JSF as the STOVL Harrier replacement and FCBA. A useful fighter, and a good multi-role aeroplane, an RAF order would be extremely good for UK plc, and would give the RAF an extremely cost-effective and versatile air power tool. But it's not shiny and high tech enough for the Air Staff, I suspect.
Grimweasel,
I suspect that that question was asked by many during the early 1930s. The problem now is that the development cycle is so long that you cannot build up an air force or design and build suitable aircraft to meet an emerging threat.
I agree with you on the necessity of having forces that are well suited to expeditionary warfare. US-style stealth warplanes which must be cosseted and kept out of the rain don't necessarily fit this scenario, however, and I think you'd be surprised at how well optimised the EF Typhoon is for out-of-area operations, rapid deployment, and autonomous operation from austere bases with minimum support. The Gripen is also top-notch in this regard, thanks to Sweden's unique concept of operations.