LOL. I would like to see India try that. Topple the Bhutanese government, and then hold a fake referendum to annex it. It's gonna open another whole new can of worms. Unlike Sikkim, annexing Bhutan cannot be done quietly in this day and age. Everyone will hear about it, and with all the historical information online, all of India's past annexations will come to the surface again. Bhutan avoided British colonialism, only to be annexed by India today? It's not gonna sit well with the most of the Global South.
It would definitely create a wave of outrage and horror throughout Asia. The West is gonna have a hard time defending India's actions. Imagine how the Khalistanis in Canada and the UK are gonna react. Everyone else is gonna question why India can do it with Bhutan, but Russia can't do it with Crimea and Donbass. India will confirm itself as an aggressive, expansionist Hindu Rashtra Empire, and all it's neighbours are gonna be extra wary, even defensive against it.