I know what the 5 year rule is and like I said if you have citizenship, which is what 5 years allows, your rights are the same as mine as long as you have British citizenship.
technically speaking, one needs to live in the UK for 6 years to be able to apply (and be granted) for British citizenship (excluding situation when they got married to the Brits etc).
After 5 years, one gets Pernament Residency (in the EU law system), or, IFL (in British laws). One needs to have it for 12 months to apply for citizenship.
And yeah, those who wish to remain pernamently should obtain UK citizenship- so they would have full voting rights and could participate in elections. plus, language test and "life in the uk" test ensures that they have at least basic knowledge of host' culture and tongue.