mkt,
high antennas in the cities are difficult to get, and whichever tilt you put, there will always be reflections the cell coverage won’t be as contained as you’d need.
And putting less sites mean you’re gonna put a lot of TRX per site (3×8, 3×12 ?) The frequency planning is going to be a pure mess.
electrical tilt is favored over mechanical tilt, always. The electrical tilt can range from 0° to 14°, even more.