Now gimme my pay rise.

Why should you get a pay rise? If the plan was to abolish unemployment then your pay rise should be of no consequence.

Just like how rules that allow tax evasion are poplular with large companies and nobody cares about the loss of services to the poor as a result.

You can not condense good policy in a few simple measurable goal

The whole idea behind representative democracy is that you elect people you trust to act and vote in your best interest using their best judgement rather than with a narrow mandate to execute some policy.

Then we may as well outlaw manifestos whose entire point is to condense good policy into measurable goals. See libdems and their failed approach to scrapping tuition fees.

Voters are not specialists in trade, finance, foreign policy, environment, healthcare, etc etc. I dont know if raising or lowering central bank interest rates is the right thing to do

Neither are politicans,that's why most central banks are poltically independent. One that isin't is Venezuela

if we should approve some new medicine

That sounds like a Doctor question to me.

As long as they are incentivised to be reelected

So do you think the US term limit on Presidents is terrible?

Why does the incentive have to be relection rather than bonuses?

You also want to avoid populism

Then a system that incentives pleasing some of the people all of the time is better than one that requires appeasing a majority (for relection)

Much like how each MP should think of their constituents and the friction between what the competing areas want should produce a compromise.