I just wanted to comment on the number of aircraft types issue.
Two is actually best. Though one type is cheaper logistically, two types means you still have something flying if the other half of the fleet gets grounded for one reason or another. Idealy one type would be from the preceding generation.
Take racing car team practice as an anology. Typically there will be two cars, one based on what won last year, and the second is an innovative design which might beat the pack this year, or it might flop. So a risky model and a reliable model. Same thing with genetics in diploid organisms. Typically there is a hetrogametic gender and a homogametic gender. Same principle. Conserve what has proven successful and throw a new type in which may or may not succeed.
So I argue two aircraft types is optimal. Three is wasteful.
Furthermore, it needs to be said that fancy, 5th gen LO strike aircraft such as the F-35, really benefit from electronic attack support. Their LO characteristics really shine when EA aircraft are messing around with enemy radar.
This is why Canada should take a very close look at the RAAF model. A combination of F-35 and a SHornet/Growler Fleet is really the ideal choice at this point in time.
SAAB has poroposed an EA version of Grippen, so a JAS-39E / F-35 combo could work too. Only issue here is that the RCAF wouldn’t benefit from USN paid support and development costs. Rather, Canada would halve to pick up deveolpment costs.
There is another factor which also needs to be considered when operating two different types. While yes, operating two types would eliminate the possibility of a fleet-wide single-type failure, it also introduces an increased probability of having aircraft grounded due to a type issue. If half a nation's fighter fleet is grounded due to a failure of some kind, and there are insufficient numbers of remaining of the 'other type' aircraft to support the required operations, then that is not much better than having a single-type fleet completely grounded.
Also keep in mind that a mixed fighter aircraft fleet would have an increased cost to operate, maintain and sustain, so that either a reduced aircraft buy would be done (smaller total fleet size) or there would be an increased cost to purchase the same total number of aircraft. As a side note, with to different designs like an F-35/Gripen or F-35/Tornado combo, then a decision would need to be made on whether a single type or set of ordnance should be integrated and used, or whether different types already integrated for the respective aircraft should be purchased and stocked. Going with a single ordnance stream would simplify the logistics as well as reduce costs (apart from any required for integration) but also introduces it's own potential for an effective grounding, should there be failures with the selected type(s) of ordnance.
One of the other real issues to consider when anyone brings up some of these 4.5 gen fighters as either an alternative or adjunct to an RCAF F-35 buy, is that one really needs to keep in mind just how viable those aircraft would be in future battlespaces. At present, the F-35 design is expected to have a front line service life with 1st world air forces out until ~2050. Given that aircraft like the Typhoon, Gripen, and Super Hornet all lack the signature management features which are designed into LO aircraft like the F-22 and F-35, even if the weapon, sensor and avionics capabilities are kept at the same levels, the LO aircraft is going to be more capable and survivable. With something like that in mind, one has to really stop and consider whether pouring money into purchasing and fielding a brand new fighter that might only be suitable for front line service for another 15 years when there is another new design available which would likely be viable for 30 years...
