Cool list. If it hadn't broken the bank (and gotten me in trouble with the wife) to buy enough infantry for my all infantry Templars, I'd pick up some crusaders to try something like this.
As for suggestions, I'm not sure it's such a hot idea to have the termies walking. It breaks target saturation, for one thing (now the enemy has something to shoot at with their bolters.) Also, if you were gonna use termies, why not DS them? You're not wanting to get them into CC anyways (I hope.)
Personally, I don't think you need the termies at all, tbh. I'd drop them and instead have a high marshall ride along with one of your crusader squads (giving 10 leadership to the army for the occasional righteous zeal check.)
Tornadoes are good, but I think more tanks is the way to go here. Again, the landspeeders rear armor gives bolters something to shoot at. And like you said, that Vindi tank is probably one of the few things that will eat a lascannon shot before your crusaders will.
You've got a lot of points tied up in things that probably aren't necessary. I'm not sure the smoke will matter. Unless you play lots of Eldar, you'll get little use out of the blessed hull upgrade (that's the anti-lance one, right?) You probably only need (or want) one light for a crusader you'll use as a pushback unit (last thing you need to do is let that Tau broadside see all of your tanks to shoot you.)
I'll give more comments if I think of them.