Another tier wouldn't be too hard considering it already exists...

Open up CL when you hit say 5,000 SC in a year, and make lifetime Plat when you hit a huge milestone like 50,000 SC.

That way current tiers don't get devalued and everyone remains happy.

Current CL's will know their 'free' CL is worth 5000 SC - hense putting a real value on it to appreciate.