If he were going to change the constitution to keep himself in power, why not just scrap term limits? Or increase the Presidential term length?
The third proposed change is interesting -- "prevent dual nationals from holding public offices" -- is this a way of limiting possible Western interference in Russian politics?
In the days of the Roman Empire, upon conquering a province the Romans would take children of members of the ruling class back to Rome, to be fostered in Roman families and raised as Romans. Then, when they reached adulthood, the new Romanized Celts or Assyrians or Goths would be sent back to the land of their birth and rule as the province in Rome's name, serving Rome's interests.
The modern Rome, the United States, does exactly the same thing.
Juan Guaido is Venezuela's "acting President". He was educated at Georgetown University in Washington DC. Alexey Navalny is the "leader of the Russian opposition", he was a "world fellow" at Yale.
The US/NATO/EU bloc is eagerly awaiting the chance to replace Putin with a pro-Western neo-liberal. One who will increase national debt, implement austerity, privatize industry, gut the public sector, and open up Russia to the IMF...just like has been done all over the Western world.
So: We have rules limiting the power of the office of President, and a rule clearly aimed at making it impossible for a US-backed puppet to be inserted into said office.
Here's where we get into some hardcore speculation:
I think, having done the hard work to fix many of Russia's societal and security-related problems, Putin is seeking to make systemic changes that prevent this work being undone.
I think Putin wants to go or is at least considering it, and is trying to put rules in place to protect Russia from his possible successors.
To demonstrate my point, we should take a look at the other parts of Putin's speech -- the parts no one in the Western press is interested in discussing.
In many ways, it was a speech you could have heard coming out of Jeremy Corbyn's mouth. Laying out a vision of Russia with improved healthcare, free (hot) school meals for all children, internet access for all Russian citizens. (You can read the whole thing here.)
If a British politician made this speech, it would be considered "radical." If an American had done so, they would be called a crazy socialist. But there's more to this than just socialist economic policies.
Here is Putin on pensions:
"We have a law on this, but we should formalize this requirement in the Constitution along with the principles of decent pensions, which implies a regular adjustment of pensions according to inflation."
On minimum wage:
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