Let's start with early-1968; let's make this a W.German-centric note.
FRG Aero had been revived on F-104G production. During 1960s they explored multiple V/STOL schemes, because the perception was that runways would not be available. US participated with FRG and settled on EWR-Sud/Boeing, then Fairchild-Hiller/Republic AVS, which would have been a courageous entry to noble technology. USSR must have been dismayed when, 3/68, FRG saw sanity and chopped it. FRG then put together a Study team to replace (C)F-104G/S: FRG/Canada/Italy/Belgium/Neths. France asked me too, please and was in the team, 3-7/68, pitching Mirage G-variants. If Marianne had been demure, the team might well have chosen her: so, no Mirage 2000N, but a family of swingers to follow on from the actual Mirage family. UK would have dribbled its half-hearted UKVG; dumped it at first cost/time drift, and would have licenced F-something.
But France messed up, again. The noble work offered to FRG industry was to supply the tyres. (I jest, but you get the idea.) So the NKF75 team threw her out...and our man Healey was there as fast as a rat up a drainpipe, with no pre-conceptions about UKVG-as-best. Instead the Committees explored single seat/dual seat/daylight/all-weather, iron/nuke.
Now..do not be diverted into Belgian politicos and brown envelopes. No. What happened was that NATO found a logic to escape from the dilemma of iron or nuke on the Central Front. They rationalised that battlefield nukes (NATO's were M115 guns, Honest John, soon Sergeant SSMs) would not be employed on Day 1, maybe even 2, 3...and that a pause for thought could be imposed by iron ordnance. End-1969, NATO moved to the <200kt nuke (UK's was WE.177C, everybody else was B61), and to first sorties with iron (soon becoming quite bright, not dumb, but not yet smart). Dispersal on autobahns - G-91, Alphajet, Jaguar, (to be) AMX, maybe even NKF75. So: what was wanted was: something better than a Stuka for breakup of WarPac armour; then something to do a deeper strike with iron and come back to base, which would still exist, honest; then turn round quickly - very quickly, for one sortie with the <200kt tactical nukes. (Feel free to ask if NATO was mad...but that is how we planned it, 1970-1991).
What the NKF75 Nations decided was to collaborate on roles, not kit. Canada's CF-18, 4 Nations' F-16s did, very well, what they were assigned through 1991. UK/FRG/It chose to hold (to be Tornado) back from the iron interlude - AMX/Jaguar/Alphajet would do that - then send out the nukes on the swinger. That is why the shoals of F-104G were replaced by, relatively, so few Tornados, and is why Unit Price was higher than, say, AMX. Tornado was bespoke to a job that Canada/Neths/Belgium (Norway, Denmark...etc) did not do.
So, the A to OP's Q - what is my alternative, is that there was none. Nothing, then or now, could go deep <200ft, in winter and EW noise, with half a chance of doing the business. US pitched to FRG with everything that did fly and some that did not (F-17, F-20). US offered noble work (strong R&D innovation, technology transfer) and got nowhere, because none did the job. FRG would have to change its Tasks, if F-15G, or F-16G, or F-anythinG were taken...unless or except...F-111E/F, which was the comparable that was deployed by USAFE. So that would be the A to the Q, if FRG had chosen to forego the industrial/techno flow from Tornado. She could have had, presumably, the spec, cost and time of RAAF F-111C. But successive FRG policos, all 3 main Parties, chose to take the home product (42.5% of Tornado R&D and production work-allocation, was by FRG) if industry demonstrated its graduation from juvenile games of cheat and lie. Which it did.