... but I'm more interested in whether the observation in the tweet holds true - is this sort of appeal to voters' misgivings about India prevalent in Pakistan, or is India less of a feature in Pakistani elections?
There is a stark difference between India and Pakistan's politics. Pakistan's politics isn't India-centric, and Pakistan doesn't have any politics regarding far-rightism like BJP AKA "Hindutva". This is because the Indian matter is mostly handled by the Pakistan military.
Before 2001, Pakistan's politics mainly revolved around the influence of the military. From 2001 to 2008, in addition to the military, it revolved around War on Terror in Afghanistan. Then, from 2008 and onwards it revolved around Panama-papers and anti-corruption. Since, other major political parties like PPP, PML-N, and MMA are heavily corrupt, they demonstrated a constant clash of interests with the military. As the military has all the intelligence of their corruption, they resorted to the bashing of the military from time to time.
Unlike India, Pakistan's military is a de facto independent state institution. In the past, PML-N and PPP tried to break this culture and heavily paid their prices. Before Imran Khan (IK), PMs only signed papers regarding security and defense matters as the decisions were mostly made by the army. IK has changed the culture. He seems to have the policy to have active cooperation with the military, and we saw that during 27-Feb-2019's Indian attempted invasion on Pakistan.
IK's present government's main agenda is anti-corruption and poverty alleviation. All other major political parties seem to become feeble and inexperienced In this turf, as their traditional political practices do not seem to be working anymore. IK seems to have become extremely popular among youths, and IK's party PTI also uses social media and online platforms heavily to mobilize youths.
Because of IK's leadership and innovation skills, nasty and cheap political practices have become obsolete in Pakistan, and poverty alleviation and anti-corruption have taken the front seat. He also has backing and cooperation from the military. So, the next elections in Pakistan would become a fight of credibility and personal image.
On the other hand, since, Indian politicians do not have any real agenda, they will constantly try to feed on far-rightism and other superficial and made-up issues.
Edit: Someone pointed out that this answer doesn't talk about "Pakistan's
toxic Islam" and hence this answer lacks neutrality.
At present "Toxic Islam" doesn't play any part in Pakistan's politics. Islam may play its part in society, but it has no role in national politics. Two of the major Islamic political parties MMA and JI are almost seatless in Pakistan's parliament.
Secondly, two of the users pointed out 3 Wikipedia articles.
Wikipedia and other collaborative online/social platforms have 5 times more users from India than from Pakistan. Pakistan's population is 200 million, India has 1.2 billion. Wikipedia is effectively has become a fake news site. Some research institutions prohibit Wikipedia to be used as reference sources.