There is no doubt that something needs to be done. However this exact project was scrapped many years ago because it cost too much and it didn't resolve the issue fully. (Alternative 3)
http://www.i-70east.com/meetingminutes/CorMtng5-17_18-06/CorMtng_5-17_18-06_AltA1andAltA3.pdf
 
The city spending billions on a highway just after spending on light rail. Then when it's all finished there will be toll lanes to charge the tax payers even more money to use the extra lanes. It goes into the drainage issue and affecting City Park. There are way too many cons to even spend the time writing right now. I don't support this plan at all and I live right near City Park and often use the affected part of i70.