With the reveal of Rani Lakshmibai, it's extremely likely that Gandhi won't make it in civ 7 for a long time. It would be extremely stupid to add 4 leaders for a single country. Of course, there's America/France, but there's also the caveat that some leaders there are personas, or encompass multiple civilizations. Both Rani and Gandhi are competing for "modern anti-British Indian leader" and have a narrow range of civilizations they can fit in.
With some civs not even having leaders, I would be extremely surprised if Firaxis would add more leaders beyond Rani. Especially because it's much easier to add civs than to add leaders.
I'm happy with this, honestly. The Indian subcontinent has such a great array of leaders that could be used who are much better than Gandhi, and if I'm being honest, 2025 is a great time to kill off the 'nuclear Gandhi' meme that's plagued civ for decades. It's such a stupid and ridiculous idea that's sadly wormed its way.