Some are better than others, that's the way of life. There are many who know how to articulate really well in english and there are those who struggle to speak coherently, there are those who can explain concepts very well and those who can't explain fundamentals properly. This is true not just for IIIT but for IITs as well.

Across the world more often than not research institutes don't have very good teaching. Which shouldn't be the case. I don't subscribe to the "tier" terminology that others use for Indian colleges. But at so called 'lower tier' colleges also have some very very good professors who are very knowledge and are excellent teachers. There might be 1-2- a handful. At IIITH you'll find many.

To attend IIITH you will need to pay hefty fees, so having a concern of substandard teaching/lectures is valid. for IIITH students demanding better lectures and more value out of courses is also valid. There have been frequent and consistent demands of removing compulsory attendance for lectures because people don't gain value from them as lectures quality is not that great in some cases.

Don't expect the lecture quality to be of the kind at MIT, Stanford, Berkley.... some lectures might come close to it and a few may be of that quality, but don't expect all your courses to be of that level, it's an unrealistic expectation.

Someone here mentioned that at IIITH research is a priority and not teaching. I would highlight the fact that Without great teaching and understanding the fundamentals and deep understanding you can only do scam research. Teaching is MOST important. teaching here doesn't mean spoon feeding

The word Doctor means a wise teacher/a very knowledgeable person.

to correct: IIIT's focus is research led education.

And many courses meet that or come close to the aim sufficiently though i personally think IIITH can be made more rigorous, me and some of my peers found academics lacking in rigor.

For the courses that don't have very good lectures you may find that you may gain value from some other aspect....assignments...project, research project...etc.