People use Simbrief for routes anyway so you get everything at the same time. Seems pretty convenient already.
We already have this, when you load simbrief it calculates the time to arrival based on your altitude and cruising speed. I don’t see the need for this when third party apps do this brilliantly.
And use this to find your altitudes and speeds required
People are open to their own opinions
combine these two tools, check the estimated data on flightaware for your flight + get the charts and airport procedures on liveflight24 or so and you get as close to realism as no ingame tool will allow you. ^^