I doubt they will strip City of any titles if they find City guilty for a number of reasons, and whatever they do will set a precedent for any future case against any club. So they will have to be careful. There are all sorts of financial and technical issues such a move would create.
1)
Look at the Aguero moment, that is a peice of IP gold, voted the best Premier League moment ever. If they strip City of the title that year, that footage becomes worthless. Should the Premier League re-pay Sky and all the other broadcasters that have bought rights and made programmes featuring that footage? Obviously each programme made by Sky and many more celebrating the seasons when City won would need editing and possibly a repayment of royalties. What about the FIFA video game (FIFA 12, FIFA 14) and any IP payment made, are there clauses in these contracts? So the ripple effect on the value of IP could be very relevant.
2)
If City were stripped of a league title: does the team that finished second win the league; do you delete City's results and redraw the table; think of another way; or does no one win it? How does this affect European qualification and relegation in the relevant seasons? Who can claim losses and off whom?
3)
Should prize money for where you finished in the league be redistributed once you've decided how to reorganise the final standings?
4)
What about bets lost and bets paid out by the bookmakers? How are these resolved?
5)
Does the West Ham - Sheffield United incident set any sort of precedent. West Ham stayed up at the expense of the Blades by fielding ineligible players. West Ham didn't lose their Premier League place despite effectively cheating. There must be reasons documented why West Ham were not relegated, which would be a precedent.
6)
Results and titles have never to my knowledge been overturned in English football for any reason. If City were stripped, would this set a precedent for other historic cases to emerge? Such as the Louis Edwards slush fund ie how did a tin pot club like Manchester United who had not won a trophy for 50 years get Duncan Edwards from under Wolves noses and the nephew of Newcastle's legendary Jackie Milburn, ie Bobby Charlton, away from Newcastle United? Are Manchester United's titles in the 50s and 60s in jeopardy?
7)
Arbitration is set out in Section X of the EPL handbook and it states it is governed by the Arbitration Act 1996. Section 66-71 of this act give City the right of appeal in court for a variety of reasons, on points of law, if they've been treated unfairly etc. So any punishment could theoretically be overturned if it's not been determined in a fair, fit and proper manner, without basis etc.
Hopefully, City can prove their case, but even if they lose, I think this is all being sensationalised to sell papers (or content, click bait etc). I can't see any punishment being that harsh, 10-20 points and a fine, ie one season damaged.
Also would the owners of clubs like Brighton, Brentford, Bournemouth and many others risk personal retribution in any form from our owners or fans if they voted to expel City from the Premier League? It would cost Mansour and Co millions, and I'm sure as noble as they are publicly, they can wield the axe if they choose to on anyone or any business. Would any of these owners want to be punched by a City fan at any point in their life in the future? I know these are less savoury points to raise, but they exist nonetheless.